Word.ws English Dictionary

Synonyms of insidious

47 similar words

Another word for insidious is subtle. Other synonyms of insidious are perfidious, proditorious, traitorous, booky and dastardly.

Synonyms and similar words for insidious

adjectiveCausing harm in a stealthy, often gradual, manner.

  • subtleActing (especially causing harm) in a stealthy, often gradual, manner; insidious.

adjectiveTreacherous.

  • perfidiousOf, pertaining to, or representing perfidy; disloyal to what should command one's fidelity or allegiance.
  • proditoriousTreacherous, traitorous.
  • traitorousCharacteristic of a traitor; disloyal.
  • bookyTreacherous, snitchy, not trustworthy.
  • dastardlyTreacherous; given to backstabbing.
  • disloyalNot loyal, without loyalty.
  • double-crossingWhich double-crosses.
  • double-dealingCheating, dishonest; treacherous.
  • double-facedDeceitful; hypocritical; treacherous.
  • double-heartedTreacherous.
  • doubleheartedDeceitful; treacherous; double-crossing.
  • faithlessNot true to allegiance, duty, or vows.
  • false
  • false-heartedDisloyal, perfidious.
  • guilefulFull of guile; treacherously deceptive.
  • hollow-heartedInsincere; deceitful; treacherous; hypocritical.
  • infidelitousUnfaithful.
  • JudaslikeResembling or characteristic of Judas Iscariot; traitorous.
  • JudaslyJudaslike; traitorous.
  • nonfaithfulNot faithful.
  • Punic figurativelyPerfidious, treacherous, faithless.
  • ratlikeResembling or characteristic of a rat, whether physically or (in behavioral terms) cunning, disloyal, or cowardly.
  • recreant literary, poeticUnfaithful to someone, or to one's duties or honour; disloyal, false.
  • renegadeDeserting, treacherous, disloyal.
  • reptilian figurativelyCold-blooded, treacherous, unavoidably selfish and hostile.
  • traitorishTraitorly; treasonous.
  • traitorlikeTraitorly.
  • traitorlyLike a traitor; traitorous.
  • traitorsomeCharacteristic of a traitor; traitorous.
  • treacherous
  • treachersomeCharacterised or marked by treachery; treacherous.
  • unfaithfulNot keeping good faith; disloyal; not faithful.
  • unlealDisloyal.
  • unloyalNot loyal.
  • unsteadfastNot steadfast; wavering, unfaithful.
  • untrueNot faithful or loyal.
  • viperishSpiteful; treacherous.
  • viperousVenomous, malicious or treacherous.
  • disleal obsoleteDisloyal; perfidious.
  • falseheart obsoleteSynonym of false-hearted.
  • guiled archaicArmed with deceit; treacherous.
  • illoyal obsoleteDisloyal.
  • proditory obsoleteTreacherous, traitorous.
  • reptitious figuratively, obsoleteSynonym of reptilian: reptilelike, (figuratively) cold-blooded, treacherous.
  • swike dialectal, obsoleteDeceitful; treacherous.
  • trothless archaic, poeticUntrustworthy, treacherous.

Meaning of insidious

  1. adjective Causing harm in a stealthy, often gradual, manner.
  2. adjective Intending to entrap; alluring but harmful.
  3. adjective Treacherous.

Full definition of insidious

insidious in other languages

Questions about synonyms of insidious

What is another word for insidious?
Insidious has 47 synonyms on Word.ws, such as subtle, perfidious, proditorious, traitorous, booky, dastardly, disloyal and double-crossing.
What does insidious mean?
Insidious means causing harm in a stealthy, often gradual, manner.

Source and license

Adapted from Wiktionary: insidious (page history and authors) and the entries of the words listed. Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws grouped the synonyms and antonyms by meaning and added links. Wiktionary data of 2026-09-02.

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Cite this page: “Synonyms of insidious.” Word.ws, https://word.ws/synonyms/insidious. Based on Wiktionary, CC BY-SA 4.0.