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

Thankfully, the current occupants of the Twins are far less treacherous than their descendant Walder Frey. —Lauren Morgan, EW.com, 15 July 2024

The ultimate bad guy is a treacherous corporate bigwig played by the shiny white Ronny Cox. —Neal Rubin, Detroit Free Press, 14 July 2024

If that probability pans out, the red crabs will struggle to stay fed and hydrated through the dry season, and face a more treacherous wet season migration and breeding period. —Lauren Leffer, Popular Science, 11 July 2024

In recent years, the Darien Gap region along the Colombia-Panama border has become a human superhighway, as U.S.-bound migrants from around the world follow a treacherous path through the jungle. —Nick Miroff, Washington Post, 2 July 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