off-key

钢琴的几个音符听起来不太准。

Some notes on the piano sound a bit ___off-key.

在这么严肃的场合说这种笑话显得很不合时宜。

Telling such jokes at this formal occasion seems ___off-key.

在正式的晚宴上，他的休闲装扮显得格格不入。

His casual outfit was totally ___off-key at the formal dinner party.