Meaning of insidious

in•sid•i•ous

Pronunciation: (in-sid'ē-us), [key]

— adj.

intended to entrap or beguile: an insidious plan.
stealthily treacherous or deceitful: an insidious enemy.
operating or proceeding in an inconspicuous or seemingly harmless way but actually with grave effect: an insidious disease.

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