adjective · Hard SAT word

    Insidious

    sneaky; beguiling but harmful

    Insidious in a sentence

    The insidious disease spread silently through his body before symptoms appeared.

    Synonyms for insidious

    • sneaky
    • sly
    • treacherous

    Antonyms for insidious

    Practice insidious on real SAT questions

    Vocabulary like insidious appears on the Digital SAT in Words-in-Context questions, where you choose the word that fits a passage's meaning and tone. You can also drill this word with vocabulary flashcards.

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