1. beguiling but harmful - insidious pleasures • Similar to: seductive • Derivationally related forms: insidiousness 2. intended to entrap • Similar to: dangerous, unsafe • Derivationally related forms: insidiousness 3. working or spreading in a hidden and usually injurious way - glaucoma is an insidious disease - a subtle poison • Syn: pernicious, subtle • Similar to: harmful • Derivationally related forms: perniciousness (for: pernicious), insidiousness
