Dictionary and Thesaurus

Definition of Insidious

• (a.) Lying in wait; watching an opportunity to insnare or entrap; deceitful; sly; treacherous; -- said of persons; as, the insidious foe.
• (a.) Intended to entrap; characterized by treachery and deceit; as, insidious arts.

Synonyms of Insidious

• Pernicious
• Subtle

Antonyms of Insidious

Homophones of Insidious