Music Pitched higher or lower than the correct notes of a melody.(adjective)
Being out of accord with what is considered normal or appropriate: a high-flown, off-key speech by a newcomer. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "off-key" in a sentence
"In this case, it sounds as if the President blew off the question so, if it was orchestrated, the orchestra was off-key."
"Eyes closed, she danced with the woman in her memory, slipping into her own off-key hum to accompany her steps when the words failed her."
"The unconscionable truth fused his mind, body and soul in a foreign uncertainty and the rhythm that had heretofore produced harmony in his life was now off-key."