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

• Wily
• Treacherous
• Designing
• Dangerous
• Deceitful
• {[Ely]?}
• Crafty
• Artful.

Antonyms of Insidious

• Straightforward
• Sincere
• Undesigning
• Innocuous.

Homophones of Insidious