- 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
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- not in the correct key
- out of tune
- out of keeping; discordant
Word Origin and History for off key
Online Etymology Dictionary, © 2010 Douglas Harper