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

Another round of winter weather will sweep across Colorado’s Front Range and Eastern Plains on Friday, with forecasters expecting treacherous road conditions and nearly 3 feet of snow in some areas. —Katie Langford, The Denver Post, 7 Nov. 2024

Explaining electoral college math feels easy peasy (thank you, genius New York Times graphics) compared to the treacherous emotional terrain many of us will cross this week. —Chloe Schama, Vogue, 5 Nov. 2024

But nobody needs to tell the media world about some of the more treacherous alleyways for a business that brings in or sells out to private equity. —Howard Homonoff, Forbes, 4 Nov. 2024

The combination of these two beliefs is uniquely treacherous for women, as this case has proved. —Belinda Luscombe, TIME, 30 Oct. 2024

Word History

First Known Use

14th century, in the meaning defined at sense 2

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