treacherous

adjective

treach·​er·​ous ˈtre-chə-rəs 

ˈtrech-rəs

1

a

: likely to betray trust : unreliable

a treacherous memory

b

: providing insecure footing or support

treacherous quicksand

c

: marked by hidden dangers, hazards, or perils

2

: characterized by or manifesting treachery : perfidious

treacherously adverb

treacherousness noun

Synonyms

• disloyal
• faithless
• false
• fickle
• inconstant
• perfidious
• recreant
• traitorous
• unfaithful
• untrue

Choose the Right Synonym for treacherous

faithless, false, disloyal, traitorous, treacherous, perfidious mean untrue to what should command one's fidelity or allegiance.

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

Examples of treacherous in a Sentence

a treacherous act of betrayal

They were not prepared to hike over such treacherous terrain.

The snow made their hike all the more treacherous.

Discussions about money can lead couples into treacherous territory.

Recent Examples on the Web

School districts opted to cancel class or switch to virtual learning throughout the eastern U.S. and as far west as Oklahoma, citing dangerously low temperatures and treacherous travel conditions. —Gabe Hauari, USA TODAY, 20 Feb. 2025

As President Donald Trump pushes to regain control of the waterway, Panamanian President José Raúl Mulino offered his country as a transit hub for U.S. deportees, aiming to curb migration through the treacherous Darién Gap. —Matt Robison, Newsweek, 19 Feb. 2025

With the help of her boyfriend (Tyler Lepley) – a former cop turned private investigator – Marley’s search for what really happened leads her down a treacherous maze of deception and betrayal. —Demicia Inman, VIBE.com, 19 Feb. 2025

The ancient Greek epic illustrates a true hero’s journey as the titular figure faces Polyphemus the Cyclops, Sirens, the nymph Calypso and the witch goddess Circe in the treacherous oceans that separate him from his island home and wife Penelope. —Max Goldbart, Deadline, 17 Feb. 2025

Word History

First Known Use

14th century, in the meaning defined at sense 2

Rhymes for treacherous

• lecherous

Kids Definition

treacherous

adjective

treach·​er·​ous ˈtrech-(ə-)rəs 

1

a

: guilty of treachery

b

: likely to betray : unreliable

a treacherous memory

2

: giving a false appearance of safety or solidity

a treacherous stretch of bog

treacherously adverb