By a complaint filed in Superior Court, the plaintiffs *465claimed that a police officer, employed by the city of Springfield (city), unlawfully invaded a restricted area of their family-owned convenience store, brutally beat them, made false arrests, used excessive force, and filed a false report. One injured plaintiff was a female child. Two adult plaintiffs — Nicole Jones and William Owens — were charged with disorderly conduct and assault and battery on an officer, the latter of which (see G. L. c. 265, § 13D) was punishable by up to two and one-half years in a house of correction. This violent incident occurred in June of 1999.

The officer in question — Ronald Boykan of the Springfield police department (department) — conducted the premises search and made the individual arrests, without a warrant or probable cause. At trial, more than one year later, a jury exonerated Nicole Jones and William Owens of all charges. The plaintiffs then filed a citizens’ complaint with the department,4 seeking redress for the harm they had suffered at the hands of Officer Boykan. An internal investigation resulted in modest disciplinary action against him: he was required to attend remedial classroom training, but he was not required to make restitution. Apart from their injuries, the plaintiffs incurred burdensome medical costs. As a further consequence, as they were of modest means, the plaintiffs suffered the loss of the family business. These core facts, found by the motion judge, are not reasonably disputed.

Procedural history. In June, 2003, the plaintiffs brought an action in Superior Court against Officer Boykan and the city’s police department. Their complaint plausibly raised claims under 42 U.S.C. § 1983 and State law.5 Service of process was made on the defendants, as of September 23, 2003, by way of hand *466delivery and certified mail, addressed to the city clerk and business office of the department.6 The complaint went unanswered.

The city was properly served,7 and although Boykan was not served at his last known residence, see Mass.R.Civ.P. 4(d)(1), as amended, 370 Mass. 918 (1976), he admitted he had “actual notice” of the complaint in 2003. Thus, there was an empty period of at least seven months when the complaint remained unanswered by him, prior to the date — July 26, 2004 — when the court ordered a default judgment to enter against him.

Notably, on December 1, 2003, some sixty days from the date of service, the Springfield law department, on behalf of both defendants, caused to be served on the plaintiffs a two-sentence motion under Mass.R.Civ.P. 12(b)(6), 365 Mass. 754 (1974), and a two-page supporting memorandum, in accordance with Superior Court Rule 9A (1989). In the motion, the defendants argued that certain claims of the plaintiffs were either time-barred, legally insufficient, or both. The plaintiffs, in turn, served an opposition and a written demand for a hearing on the motion.

For unknown reasons, the defendants abandoned their rule 12 motion. They neither filed it nor presented it to the Superior Court.8 The motion itself did not raise a defense of insufficient service of process, or its corollary, of a want of personal jurisdiction. The prevailing interpretation of Mass.R.Civ.P. 12(h), *467365 Mass. 757 (1974), requires a defendant to raise an affirmative defense — including but not limited to insufficient service of process — within “a reasonable time and prior to participating in discovery and litigating the merits of the case,” or run the risk of having such a defense deemed waived. Raposo v. Evans, 71 Mass. App. Ct. 379, 383 (2008). See id. at 383-384 & n.15, citing Federal decisions construing the parallel Fed.R. Civ.R 12(h)(1). If made aware of a service of process flaw, the plaintiffs could have easily remedied the same with leave of court. See Mass.R.Civ.R 4(g), 365 Mass. 733 (1974), and the 1973 Reporters’ Notes thereto, Mass. Ann. Laws Court Rules, Rules of Civil Procedure, at 27 (LexisNexis 2010-2011), citing G.L. c. 231, § 51.9

Moreover, the defendants took no action over the following six-month time period, between December 2, 2003, and June 2, 2004. They did not attend duly-noticed hearings, neglected to provide discovery, and offered no excuse for ignoring the case at hand.

Subsequently, on June 3, 2004, the clerk issued a default against the defendants, see Mass.R.Civ.P. 55(a), 365 Mass. 822 (1974). Nearly two months later, on July 26, after having held a hearing, the motion judge ordered the entry of a default judgment pursuant to Mass.R.Civ.P. 55(b)(2), awarding damages in the amount of $1 million against the defendants.

This prompted the defendants, on August 4, to file an “emergency” motion to vacate the default judgment. The default judgment was entered on August 9, 2004, and the defendants’ motion was heard on September 14. The motion judge denied the requested relief. The judge ruled that the grounds cited by the defendants for relief under Mass.R.Civ.P. 60(b), 365 Mass. 828 (1974), lacked merit, and added that justice would not be *468served in this case by “relieving the defendants from their conscious, extended, and unjustified inattention” to the case.10 The judge characterized the defendants’ contentions that they had been disadvantaged by inadequate service of process as being, at best, “disingenuous.”

The defendants’ renewed motion, filed on November 2, 2004, did not raise any different ground for reconsideration of the denial of their original rule 60(b) motion. The judge changed course, however, and in an order dated June 30, 2005, allowed the renewed motion insofar as it sought an order vacating the default judgment vis-a-vis Boykan because of the plaintiffs’ technically deficient service of process.11 The judge concluded that Boykan did not waive a defense of insufficiency of service of process. The combined rulings were error as matter of law.12

Discussion. 1. Rule 60(b). Rule 60(b) of the Massachusetts Rules of Civil Procedure provides a limited exception to the finality of a judgment. Relief is available in a narrow set of circumstances, specified in subdivisions (b)(1) through (b)(6), to accomplish justice. “Properly applied Rule 60 (b) strikes a balance between serving the ends of justice and preserving the finality of [a] judgment^.” Harris v. Sannella, 400 Mass. 392, 395 (1987), quoting from Nemaizer v. Baker, 793 F.2d 58, 61 (2d Cir. 1986). That appropriate balance, between finality and justice, was turned on its head in this case.

Even though rule 60(b) allows for a considerable measure of discretion in its application, a judge is not permitted, in exercis*469ing that discretion, to grant relief to a party absent a showing of good cause or excusable neglect, see Gath v. M/A-Com, Inc., 440 Mass. 482, 497 (2003) and the existence of a meritorious defense. See Berube v. McKesson Wine & Spirits Co., 7 Mass. App. Ct. 426, 430 (1979); Tai v. Boston, 45 Mass. App. Ct. 220, 222 (1998). The motion judge did not find that any such showing was made here by Boykan, so as to permit the issuance of relief under subdivision (b)(1), the excusable neglect exception,13 or that of (b)(6), the catch-all provision, available only in exotic or exceptional circumstances,14 not shown to be present in this case.

The only possible ground for relief under rule 60(b) was its quite narrow exception, provided for by subdivision (b)(4), which applies only in the circumstance when a judgment is “void” as matter of law. We review de novo the judge’s decision along this line. See Field v. Massachusetts Gen. Hosp., 393 Mass. 117, 118 (1984), citing Reporters’ Notes to Mass.R.Civ.P. 60(b)(4), Mass. Ann. Laws, Rules of Civil and Appellate Procedure at 586 (Law. Co-op. 1982) (“Rule 60[b][4] allows relief only from void judgments. A court must vacate a void judgment. It may not vacate a valid one. No discretion is granted by the rule”).

Indisputably, Boykan had actual notice of the complaint well in advance of the entry of the default judgment. Despite any flaw or shortcoming of a technical nature, neither was personal jurisdiction wanting nor was there a failure by the plaintiffs to abide by due process requirements. See Eastern Sav. Bank v. Salem, 33 Mass. App. Ct. 140, 143 (1992), citing Bowers v. Board of Appeals of Marshfield, 16 Mass. App. Ct. 29, 32 (1983). Boykan had at all material times adequate notice of the complaint and a meaningful opportunity to be heard in answer to the claims raised. See Mullane v. Central Hanover Bank & Trust Co., 339 U.S. 306, 314 (1950). No prejudice accrued to him. The judgment was not void, as matter of law, as that concept is understood by rule 60(b)(4). See Atlas Elevator Co. *470v. Stasinos, 4 Mass. App. Ct. 285, 287-288 & n.2 (1976); City Council of Waltham v. Board of Appeals of Waltham, 5 Mass. App. Ct. 773, 774 (1977). Inherent in the concept of a void judgment is an act of usurpation of authority by the court, a rare circumstance that is unquestionably not present here. See United Student Aid Funds, Inc. v. Espinosa, 130 S. Ct. 1367, 1377 (2010); Harris v. Sannella, 400 Mass. at 395.

In Espinosa, the United States Supreme Court made it quite clear that rule 60(b)(4) “applies only in the rare instance where a judgment is premised either on a certain type of jurisdictional error or on a violation of due process that deprives a party of notice or the opportunity to be heard.” Ibid. For a unanimous Court in Espinosa, Justice Thomas ruled that although a debtor’s failure to cause a summons and complaint to be served on a creditor had deprived the latter of a right afforded by a procedural rule in an action in the United States Bankruptcy Court, the deprivation did not amount to a violation of the creditor’s due process rights. 130 S. Ct. at 1378. The Court held: “Where . . . a party is notified of a plan’s contents and fails to object to confirmation of the plan before the time for appeal expires, that party has been afforded a full and fair opportunity to litigate, and the party’s failure to avail itself of that opportunity will not justify Rule 60(b)(4) relief.” Id. at 1380.

It works no deprivation of due process to hold that a personal defense of insufficiency of service of process may be waived by an individual defendant’s failure to timely assert it, where, as here, it has been made to appear that the party not only has had actual notice of the complaint but also has, by word or deed, implicitly submitted to the court’s jurisdiction. See Insurance Corp. of Ireland, Ltd. v. Compagnie des Bauxites de Guinee, 456 U.S. 694, 703 (1982) (“Because the requirement of personal jurisdiction represents first of all an individual right, it can, like other such rights, be waived”). Compare Raposo v. Evans, 71 Mass. App. Ct. at 385. Any different conclusion would yield a maze of contradictions.

Having had actual notice of the action, the defendants failed entirely to show any reasonable explanation for neglecting to inquire as to the status of the case until filing an emergency motion in response to the default judgment. See Scannell v. Ed. Ferreirinha & Irmao, Lda., 401 Mass. 155, 161 (1987), quoting *471from Taylor v. Boston & Taunton Transp. Co., 720 F.2d 731, 732-733 (1st Cir. 1983) (“The reasonable course of action for [the defendants] to have followed would have been to make some further inquiry ... to ascertain the true status of the case. Instead . . . [the defendants] did nothing until after receiving a copy of the final judgment”). The default judgment, produced by the defendants’ own wilful conduct, must stand.

2. Interests of justice. “Unlike most private tort litigants, a civil rights plaintiff seeks to vindicate important civil and constitutional rights that cannot be valued solely in monetary terms.” City of Riverside v. Rivera, 477 U.S. 561, 574 (1986). Redress of harms resulting from the misconduct of police officers, offensive to well-settled constitutional standards of reasonableness, decency, and fairness, implicit in the concept of ordered liberty, must be available, without injurious delay to all citizens equally. That was the egregious error here, and no further delay can be countenanced.

The city makes no attempt to defend the conduct of its officer. Inferentially, its tepid disciplinary action displayed an indifference to, if not a ratification of, that actionable conduct. “Our Government is the potent, the omnipresent teacher. For good or for ill, it teaches the whole people by its example.” Olmstead v. United States, 277 U.S. 438, 485 (1928) (Brandéis, J., dissenting). The city failed to teach by positive example and instead with its police officer bred contempt in its citizenry for agents of law enforcement.

Conclusion. The judgment dated February 16, 2007, and the amended judgment dated April 12, 2007, are reversed, as is so much of the order of June 30, 2005, as granted relief to Boykan and the city from the binding terms of the default judgment. The default judgment and damages award entered on August 9, 2004, shall be reinstated in all respects against the city and Boykan, with all due ministerial modifications, including interest and court costs.15

So ordered.