underbreath
Etymology
From under- + breath.
adj
- Vocalized under one's breath.“Aleck gave a low, underbreath whistle.”
adv
- Under one's breath; inaudibly or in a barely audible manner.“Muttering curses underbreath, he jabs the beast sharply with his training stick ; the elephant is hairy and it, like the clown, is ignoble.”
noun
- An utterance made so as not to be heard by most people in the area.“The underbreath of our every prayer should be, “Father, not my will, but thine be done””