inaudible

Kirkwood settled himself with an inaudible sigh of pleasure.

He managed to make it inaudible, however; and it was as well that he did.

Under cover of the music her voice was inaudible to any one else.

The other voice was lower in key and the words were inaudible.

The cabman got on to his box, muttering something that was inaudible.

That terrific holocaust of death and destruction was inaudible.

I could see now and then that he was speaking, but he was inaudible.

He was, as great orators will sometimes be, “inaudible in the gallery.”

Once the night fell the sea was the smuggler's own: he was invisible, inaudible.

Mrs. Medley's reply was inaudible, but apparently in the affirmative.