What does "judas" mean?

Judas: The disciple who betrayed Christ. Hence: A treacherous person; one who betrays under the semblance of friendship. -- a. Treacherous; betraying. Judas hole, a peephole or secret opening for spying. -- Judas kiss, a deceitful and treacherous kiss. -- Judas tree (Bot.), a leguminous tree of the genus Cercis, with pretty, rose-colored flowers in clusters along the branches. Judas is said to have hanged himself on a tree of this genus (C. Siliquastrum). C. Canadensis and C. occidentalis are the American species, and are called also redbud.