adjective.
Lying in wait; watching an opportunity to insnare or entrap; deceitful; sly; treacherous; -- said of persons.
adjective.
Intended to entrap; characterized by treachery and deceit.
adjective.
Acting or proceeding unobserved or in a seemingly harmless manner, but slowly or eventually doing great damage.
adjective.
a disease existing, without marked symptoms, but ready to become active upon some slight occasion; a disease not appearing to be as bad as it really is.