n. Deceit; duplicity. [ 1913 Webster ]

Now cometh the sin of double-tongue, such as speak fair before folk and wickedly behind. Chaucer. [ 1913 Webster ]

a. Making contrary declarations on the same subject; deceitful.
Syn. -- deceitful, double-faced, hypocritical, Janus-faced, two-faced. [ 1913 Webster ]

Likewise must the deacons be grave, not double-tongued. 1 Tim. iii. 8. [ 1913 Webster ]

n. (Mus.) A peculiar action of the tongue by flute players in articulating staccato notes; also, the rapid repetition of notes in cornet playing. [ 1913 Webster ]