Definition for Insidious:

• Lying in wait; watching an opportunity to insnare or entrap; deceitful; sly; treacherous; - said of persons; as, the insidious foe.

Synonyms for Insidious:

• adj.

  •deceptive (adjective)
  • false,
  • treacherous,
  • ensnaring,
  • stealthy,
  • dishonest,
  • secret,
  • sly.
  •dishonest (adjective)
  • deceptive.
  •sneaky, tricky (adjective)
  • deceptive,
  • stealthy,
  • treacherous,
  • machiavellian,
  • ensnaring,
  • dangerous,
  • intriguing,
  • corrupt,
  • like a snake in the grass,
  • deep,
  • perfidious,
  • subtle,
  • astute,
  • wily,
  • smooth,
  • slick,
  • crafty,
  • disingenuous,
  • false,
  • sly,
  • guileful,
  • wormlike,
  • artful,
  • perilous,
  • secret,
  • duplicitous,
  • snaky,
  • deceitful,
  • designing,
  • foxy,
  • crooked,
  • sneaking,
  • dishonest,
  • surreptitious,
  • cunning.
  •underhand (adjective)
  • lubricious.

• n.

  •
  • perilous.
  •insidious (noun)
  • seductive,
  • harmful,
  • subtle,
  • pernicious,
  • unsafe,
  • dangerous.

• Other synonyms:

  •
  • dishonest.
  •crafty
  • devious,
  • sly.
  •Other relevant words:
  • devious,
  • secretively,
  • shameful,
  • guile,
  • finagling,
  • canny,
  • malevolent,
  • deceitfulness,
  • rebel,
  • cattiness,
  • slimy,
  • elusive,
  • disingenuous,
  • resourceful,
  • perfidious,
  • leery,
  • corrupting,
  • fraudulent,
  • astute,
  • suspicious,
  • secret,
  • covert,
  • unprincipled,
  • prejudicial,
  • false,
  • sneaky,
  • mephistophelian,
  • downy,
  • treacherousness,
  • deceptive,
  • snaky,
  • malicious,
  • trap,
  • acute,
  • clever,
  • tattler,
  • delusive,
  • deadly,
  • perfidy,
  • byzantine,
  • immoral,
  • feline,
  • dodgy,
  • guileful,
  • Subtile,
  • evil,
  • surreptitious,
  • untrue,
  • calculating,
  • sneaking,
  • black,
  • perilous,
  • malign,
  • atrocious,
  • awful,
  • blackguardly,
  • manipulative,
  • arch,
  • flagitious,
  • Deceived,
  • devilish,
  • dubious,
  • prestigious,
  • strategic,
  • wary,
  • perfidiousness,
  • rotten,
  • illusive,
  • dishonesty,
  • foxy,
  • insincere,
  • knowing,
  • tricky,
  • base,
  • shifty,
  • insidiousness,
  • questionable,
  • wicked,
  • vicious,
  • traitorous,
  • doubtful,
  • supple,
  • Deceptious,
  • outrageous,
  • hypocritical,
  • cute,
  • foul,
  • telltale,
  • jesuitical,
  • pawky,
  • smooth,
  • unsavory,
  • corrupted,
  • slick,
  • dastardly,
  • iniquitous,
  • fishy,
  • roguish,
  • crooked,
  • dirty,
  • shrewd,
  • sneakily,
  • unspeakable,
  • casuistic,
  • treasonable,
  • dark,
  • ad captandum vulgus,
  • Deceiving,
  • betrayer,
  • amoral,
  • charged,
  • baleful,
  • abominable,
  • collusive,
  • ready,
  • tactical,
  • diabolical,
  • delusory,
  • shameless,
  • Prestigiatory,
  • Subtleties,
  • untrustworthy,
  • nuance,
  • mischievous,
  • ill-gotten,
  • falsehearted,
  • underhand,
  • wily,
  • traitor,
  • Ill-got,
  • treacherous,
  • designing,
  • wormlike,
  • illusory,
  • sinister,
  • treasonous,
  • hellish,
  • Contriving,
  • tricksy,
  • unfaithful,
  • clandestinely,
  • slim,
  • craft,
  • reptilian,
  • surreptitiously,
  • knavish,
  • evasive,
  • villainous,
  • machiavellian,
  • conscienceless,
  • dishonorable,
  • skillful,
  • politic,
  • hidden,
  • inventive,
  • artificial,
  • sly,
  • unconscientious,
  • deceitful,
  • stealthy,
  • sophistical,
  • furtive,
  • nefarious,
  • deepness,
  • stealthily,
  • cagey,
  • deep-laid,
  • Chiseling,
  • smarmy,
  • timeserving,
  • unconscionable,
  • infernal,
  • lubricious,
  • duplicitous,
  • felonious,
  • underhanded,
  • Subdolous,
  • treachery,
  • shady,
  • Trickish,
  • cunning,
  • crafty,
  • beguiling,
  • conniving,
  • ingenious,
  • indirect,
  • criminal,
  • not kosher,
  • profound,
  • secretly,
  • unethical,
  • sharp,
  • covertly,
  • pestilent,
  • subtlety,
  • baneful,
  • corrupt,
  • slippery,
  • janus-faced,
  • up to snuff,
  • scheming,
  • artful,
  • diabolic,
  • Double dealing,
  • gradual,
  • vulpine,
  • malignant,
  • ensnaring,
  • Covinous,
  • loaded,
  • serpentine,
  • deep,
  • disloyal,
  • intriguing,
  • satanic,
  • two-faced,
  • bad,
  • scurvy,
  • diplomatic,
  • profundity,
  • like a snake in the grass,
  • smart,
  • harmfulness,
  • dishonourable,
  • depth,
  • skilful,
  • Plotting,
  • tortuous,
  • furtively,
  • disgraceful,
  • vile,
  • dishonest,
  • prejudiced,
  • unscrupulous,
  • faithless.

Antonyms for Insidious:

• adj.

  • sneaky, tricky
    honest, sincere, fair, open.
  • Other antonyms:
    safe, unseductive.

• Other antonyms:

  • n. t.
    artless, conspicuous, fair, forthright, honest, ingenuous, obvious, open, sincere, straightforward, upright.