The Collaborative International Dictionary
Double dealer \Dou"ble deal"er\, double-dealer \dou"ble-deal"er\
One who practices double dealing; a deceitful, trickish
person; a person who says one thing and does another.
--L'Estrange.
Syn: double-crosser, betrayer, traitor.
Wiktionary
n. One who double deals. A cheat or crook.
WordNet
n. a person who says one thing and does another [syn: double-crosser, two-timer, betrayer, traitor]
Usage examples of "double-dealer".
Not only are you incapable of double-dealing, not only are you incapable of thinking along double-dealing lines, you're not even capable of thinking of the consequences to the double-dealer who has overplayed his hand.
The breach was healed, but Defoe seems to have realised that his days as a double-dealer were numbered.
But it was plain that Sefris was as treacherous a double-dealer as most everyone else she'd met in Oeble, and had been playing her for a fool from the start.
And what those double-dealers couldn't pull from HQ, they hoped to learn from her!