1. a betrayal or swindle of a colleague.
2. an attempt to win a contest that one has agreed beforehand to lose. Cf. cross (def. 21).
3. Genetics.a cross in which both parents are first-generation hybrids from single crosses, thus involving four inbred lines.
Pronunciation: (dub'ul krôs', -kros'),[key] —v.t.Informal. to prove treacherous to; betray or swindle, as by a double cross.