Synonyms of treacherous

treacherous

adjective

ˈtre-chə-rəs 

as in traitorous

not true in one's allegiance to someone or something

a treacherous "friend," she's been known to turn against people in the blink of an eye

Synonyms & Similar Words

• traitorous
• unreliable
• false
• disloyal
• perfidious
• faithless
• fickle
• unfaithful
• inconstant
• untrue
• untrustworthy
• recreant
• irresponsible
• hesitant
• uncertain
• undependable
• faltering
• dubious
• irresolute
• trustless
• dispassionate
• vacillating
• uninterested
• apathetic
• wavering

Antonyms & Near Antonyms

• constant
• loyal
• true
• faithful
• steadfast
• responsible
• steady
• fast
• reliable
• staunch
• devout
• trustworthy
• solid
• dependable
• dedicated
• devoted
• down-the-line
• trusty
• dutiful
• tried
• resolute
• unfaltering
• determined
• unhesitating
• trustable
• inveterate
• intent
• passionate
• confirmed
• tried-and-true
• enthusiastic
• impassioned
• ardent
• unwavering
• sworn
• fervent
• avid
• fervid
• dyed-in-the-wool

Synonym Chooser

How is the word treacherous different from other adjectives like it?

Some common synonyms of treacherous are disloyal, faithless, false, perfidious, and traitorous. While all these words mean "untrue to what should command one's fidelity or allegiance," treacherous implies readiness to betray trust or confidence.

a treacherous adviser

When can disloyal be used instead of treacherous?

Although the words disloyal and treacherous have much in common, disloyal implies a lack of complete faithfulness to a friend, cause, leader, or country.

disloyal to their country

When could faithless be used to replace treacherous?

While in some cases nearly identical to treacherous, faithless applies to any failure to keep a promise or pledge or any breach of allegiance or loyalty.

faithless allies

Where would false be a reasonable alternative to treacherous?

The words false and treacherous are synonyms, but do differ in nuance. Specifically, false stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery.

betrayed by false friends

How do perfidious and faithless relate to one another, in the sense of treacherous?

Perfidious adds to faithless the implication of an incapacity for fidelity or reliability.

a perfidious double-crosser

When is traitorous a more appropriate choice than treacherous?

The synonyms traitorous and treacherous are sometimes interchangeable, but traitorous implies either actual treason or a serious betrayal of trust.

traitorous acts punishable by death

Example Sentences

Recent Examples of treacherous

Several regions suspended transit service or issued bans on road travel amid treacherous conditions. —Samuel Hart, CNN Money, 23 Feb. 2026

The weather service warned that travel will be treacherous, with blowing snow causing low visibility. —Leslie Josephs, CNBC, 23 Feb. 2026

At least seven governors declared states of emergency as powerful wind gusts up to 70 mph cause coastal flooding, power outages and treacherous roads. —Phil Helsel, NBC news, 23 Feb. 2026

Maryland leaders are warning of treacherous travel conditions overnight, especially along the Eastern Shore, where there is a blizzard warning. —Adam Thompson, CBS News, 22 Feb. 2026