double-dealing 
noun [mass noun]
The practice of working to people’s disadvantage behind their backs: an air of double-dealing and deceit hangs over the negotiations...
- His prior record of deception, double-dealing, and concealment makes that quite impossible.
- She hits back, setting into motion an unlikely but highly watchable tale of deceit, double-dealing, divorce and international fraud.
- By and large, he is a dramatist of deception and double-dealing, an architect of environments that entrap and extinguish their inhabitants.
Synonyms
duplicity, treachery, betrayal, double-crossing, faithlessness, unfaithfulness, untrustworthiness, infidelity, bad faith, disloyalty, perfidy, perfidiousness, treason, breach of trust, fraud, fraudulence, underhandedness, cheating, dishonesty, deceit, deceitfulness, deception, falseness, stab in the back, back-stabbing, lying, mendacity, trickery, two-facedness
informal crookedness, two-timing
rare Punic faith
adjective
Working deceitfully to injure others: she is a back-stabbing, double-dealing twister...
- Or is he a desperate, double-dealing politician fishing for votes in the San Fernando Valley?
- Part of the problem with Out of Time is that most audiences will be way ahead of the double-dealing plot.
- This dastardly double-dealing duo plays quite well together, injecting a great deal of sinister, urbane menace into the movie, and adding extra levels of complexity to the story.
Derivatives
double-dealer
/ noun ...- What stinks worse is the concept that people don't suddenly turn into bad guys, or conceited double-dealers for just one case.
- Gabriel turned out to be a shameless double-dealer.
- Sure, he provided good intelligence on his trading partners in Havana, but he was also a double-dealer who was passing him who-knew-how-many secrets of ours.