off-key — OET

off-key

adjective

1 a slightly off-key rendition of an old family favourite:

out of tune, flat, tuneless, unmusical, unmelodic, discordant, dissonant, unharmonious.

▷antonyms in tune.

2 some of the cinematic effects are distractingly off-key:

incongruous, inappropriate, unsuitable, discordant, out of place, out of keeping, jarring, dissonant, inharmonious.

▷antonyms harmonious.

off-key Oxford Dictionary of English