The meaning of INSIDIOUS is causing harm in a way that is gradual or not easily noticed; especially : having a gradual and cumulative negative effect. How to use insidious in a …

When To Use What does insidious mean? Insidious describes something as being sneaky or being secretly dangerous or harmful.

INSIDIOUS definition: 1. (of something unpleasant or dangerous) gradually and secretly causing harm: 2. (of something…. Learn more.

If something is slowly and secretly causing harm, it's insidious — like the rumors no one seems to listen to until suddenly someone's reputation is ruined.

Definition of insidious adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

1. Working or spreading harmfully in a subtle or stealthy manner: insidious rumors; an insidious disease. 2. Intended to entrap; treacherous: insidious misinformation. 3. Beguiling but harmful; …

insidious (adjective) insidious /ɪn ˈ sɪdijəs/ adjective Britannica Dictionary definition of INSIDIOUS [more insidious; most insidious] formal : causing harm in a way that is gradual or not easily …

Definition of insidious. English dictionary and integrated thesaurus for learners, writers, teachers, and students with advanced, intermediate, and beginner levels.

Insidious definition: Working or spreading harmfully in a subtle or stealthy manner.

Something that is insidious is unpleasant or dangerous and develops gradually without being noticed. The changes are insidious, and will not produce a noticeable effect for 15 to 20 years. …