double-cross

Etymology
First recorded in 1834 from thieves' slang (or ) to refer to something dishonest, a play on straight/square: a crook going back on his partners would therefore be crossing the crossers, or double-crossing.

Verb

 * 1) To betray or go back on; to deceive someone after having gained their trust and led them to believe that they were being aided.
 * 2)  To cross twice in hybridization, as (A × B) × (C × D); for example, in commercial hybrid seed corn, A through D are classically inbreds, and their grandoffspring is the seed for sale.
 * 1)  To cross twice in hybridization, as (A × B) × (C × D); for example, in commercial hybrid seed corn, A through D are classically inbreds, and their grandoffspring is the seed for sale.

Translations

 * Bulgarian:, , играя двойна игра
 * Chinese:
 * Mandarin: ,
 * German:, aufs Kreuz legen, ein Doppelspiel treiben mit
 * Greek:
 * Russian: ,

Noun

 * 1) An instance of betrayal of one who had been led to believe that the betrayer was assisting them.
 * 2)  The hybrid product of double-crossing.