insidious

1. 1.

   beguiling but harmful

   “insidious pleasures”

   Similarseductive
2. 2.

   intended to entrap

   Similardangerous
3. 3.

   working or spreading in a hidden and usually injurious way

   “glaucoma is an insidious disease”

   “a subtle poison”

   Synonymspernicioussubtle

   Similarharmful

Questions about insidious

What does insidious mean?

insidious means "beguiling but harmful". That is the primary sense; the word has 3 in total, listed in full on this page.

How many syllables are in insidious?

insidious has 4 syllables: in-sid-i-ous. The stress falls on "sid". In IPA it is /ˌɪnˈsɪˌdiəs/.

What is another word for insidious?

Close synonyms include pernicious, subtle. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.

Is insidious a common word?

insidious is banded "Familiar" — widely understood, used when the subject calls for it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.