Definition of insidious :
1. Intended to entrap; characterized by treachery and deceit; as, insidious arts.
2. Lying in wait; watching an opportunity to insnare or entrap; deceitful; sly; treacherous; - said of persons; as, the insidious foe.
deceptive (part of speech: adjective)
- Mrs. Hudson looked at first as if this could be but an insidious device for increasing her distress by the assistance of irony. - "Roderick Hudson", Henry James.
- " But ever prowls th' insidious foe, And listens round the fold" This was too much. - "The Delectable Duchy", Arthur Thomas Quiller-Couch.
- He asked De Vayne to a dessert, and took care that the wines should be of an insidious strength. - "Julian Home", Dean Frederic W. Farrar.