faithless applies to any failure to keep a promise or pledge or any breach of allegiance or loyalty.
faithless allies
false stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery.
betrayed by false friends
disloyal implies a lack of complete faithfulness to a friend, cause, leader, or country.
disloyal to their country
traitorous implies either actual treason or a serious betrayal of trust.
traitorous acts punishable by death
treacherous implies readiness to betray trust or confidence.
a treacherous adviser
perfidious adds to faithless the implication of an incapacity for fidelity or reliability.
a perfidious double-crosser
Example Sentences
when our coach took a job at a rival college, a few traitorous players went right along with him
Recent Examples on the WebTo prevent self-destruction, the immune system relies on an intricate series of fail-safes that are collectively termed self-tolerance to identify and eliminate potentially traitorous immune cells. Matthew Woodruff, The Conversation, 31 Aug. 2022 One supposedly traitorous soldier — also Black — is ordered to be executed by his nervous, boyish, anachronistically mohawked mate Ze (João Arrais), who glumly resists the praise then lavished on him by superiors. Guy Lodge, Variety, 9 Aug. 2022 That language clashed markedly with hard-line rhetoric emanating from Moscow, where supporters of the war, who do not consider Ukraine to be a legitimate country, denounced Mr. Medinsky’s diplomacy as bordering on traitorous.New York Times, 30 Mar. 2022 This was a sharp departure from a tradition under which those who reported crimes by fellow Haredim were viewed as traitorous informers. Joseph Berger, New York Times, 18 Mar. 2022 As the fighting in the east has raged, their sermons are often seen as overly forgiving of Moscow’s ambitions in Ukraine, or even traitorous.Washington Post, 7 Feb. 2022 Announcers—conditioned to steer fans to feel a certain way about characters on the show—gently suggested his selfish or traitorous tendencies to deaf ears. Martin Douglas, SPIN, 21 Jan. 2022 In order to make up for her traitorous past, Rosalind works as a spy for her country. Sam Gillette, PEOPLE.com, 20 Jan. 2022 However, that turnabout is nothing compared with McCarthy’s head-snapping response to the violent and traitorous events of Jan. 6.Los Angeles Times, 7 Jan. 2022 See More