Definitions for "Insidious"
Keywords:  deceit, entrap, sly, insnare, treachery
Lying in wait; watching an opportunity to insnare or entrap; deceitful; sly; treacherous; -- said of persons; as, the insidious foe.
Intended to entrap; characterized by treachery and deceit; as, insidious arts.
Acting or proceeding unobserved or in a seemingly harmless manner, but slowly or eventually doing great damage; as, an insidious disease; an insidious plot.
Of subtle, gradual, or imperceptible development; referring to the development of symptoms that may not be recognized by an affected individual until the disorder in question is established.
A disease which comes on in such a manner, with a lack of symptoms, that the patient is unaware of the onset of the disease.
Keywords:  beguiling, harmful, pleasures
beguiling but harmful; "insidious pleasures"