intransitive verb Date: 1909 to play three chords before and after marching up and down a line of troops during a ceremonial parade or formal guard mount, to count cadence while marching, 3. to speak up in a loud voice, to voice one's opinions freely and vigorously
SOUND OFF
Meaning of SOUND OFF in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012