- (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.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). insidious. Retrieved September 23, 2026, from http://smartdefine.org/insidious/definitions/2022150 |
| Chicago | Webster's. 2011. "insidious" http://smartdefine.org/insidious/definitions/2022150 (accessed September 23, 2026). |
| Harvard | Webster's 2011, insidious, Smart Define, viewed 23 September, 2026, <http://smartdefine.org/insidious/definitions/2022150>. |
| MLA | Webster's. "insidious" 27 May 2011. Web. 23 September 2026. <http://smartdefine.org/insidious/definitions/2022150> |