insidious

adjective
UK: /ɪnˈsɪdiəs/
US: /ɪnˈsɪdiəs/

  1. Something that is insidious is dangerous because it seems harmless at first but causes damage over time.

    1. Cancer can be insidious and difficult to detect early on.
    2. The insidious nature of the disease meant it spread before anyone knew.

  2. Gradually and secretly causing harm; subtle but destructive.

    1. The insidious rumors damaged his reputation.
    2. Insidious changes in policy can erode our freedoms without us noticing.

Synonyms

deceitful treacherous cunning sly subtle gradual stealthy surreptitious

Frequently Asked Questions

The word "insidious" in English means: Something that is insidious is dangerous because it seems harmless at first but causes damage over time., Gradually and secretly causing harm; subtle but destructive..

The phonetic transcription of "insidious" is /ɪnˈsɪdiəs/ in British English and /ɪnˈsɪdiəs/ in American English. Click the 🔊 button to hear both pronunciations.

Synonyms for "insidious": deceitful, treacherous, cunning, sly, subtle, gradual, stealthy, surreptitious.

Example usage of "insidious": "Cancer can be insidious and difficult to detect early on.". More examples on the page.