false note

Sometimes he even thrums a little on the piano, and takes a part in a trio, in which his voice can generally be distinguished by a certain quavering tone, and an occasional false note.

[H]is words were grave, his manner was earnest, and his speech came from the fulness of his heart. If there had been a false note, a false look, Harry would have detected both.

The only false note in an otherwise classic and elegant collection was the gratuitous flash of black fishnet stockings and suspenders under otherwise unremarkable paisley and floral shirts.