utter a word

not utter a word

To be completely silent; to remain discreet (about something); to not tell anyone (about something). All the while our father was shouting at us, my sister and I didn't utter a word. Tom, don't you dare utter a word about this! I would die of embarrassment if anyone were to find out.
See also: not, utter, word
Farlex Dictionary of Idioms.

utter a word

see under not open one's mouth.
See also: utter, word
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • not utter a word
  • utter
  • open your mouth
  • not open (one's) mouth
  • not open mouth
  • not open one's mouth
  • squeak out
  • dumpster fire
  • give out with (something)
  • give out with something
References in classic literature
Of all that were there Sancho was the only one who was at once in his senses and in his own proper character, and he, though he was within very little of sharing his master's infirmity, did not fail to perceive who all these disguised figures were; but he did not dare to open his lips until he saw what came of this assault and capture of his master; nor did the latter utter a word, waiting to the upshot of his mishap; which was that bringing in the cage, they shut him up in it and nailed the bars so firmly that they could not be easily burst open.
You walk up to him at the bus stop, but you can't utter a word and your eye won't stop twitching.