Dictionary
in•sid•i•ous
Pronunciation: (in-sid'ē-us), [key]—
adj.
1. intended to entrap or beguile:
an insidious plan.
2. stealthily treacherous or deceitful:
an insidious enemy.
3. operating or proceeding in an inconspicuous or seemingly harmless way but actually with grave effect:
an insidious disease. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.