off-key

[ awf-kee, of- ]
/ ˈɔfˈki, ˈɒf- /

adjective

deviating from the correct tone or pitch; out of tune.
Informal. somewhat irregular, abnormal, or incongruous.

Origin of off-key

First recorded in 1925–30

British Dictionary definitions for off key

off key

adjective, adverb (off-key when prenominal)

music
  1. not in the correct key
  2. out of tune
out of keeping; discordant