mutter (something) under (one's) breath

mutter (something) under (one's) breath

To murmur something in such a soft, quiet voice that others cannot hear it distinctly. (Said especially of rude, unpleasant, complaining, or impertinent remarks.) I could hear Bill muttering something under his breath on the way back to his desk after his annual review. Don't you dare mutter curse words under your breath at me, young lady!
See also: breath, mutter
Farlex Dictionary of Idioms.
See also:
  • mutter
  • curse (someone) under (one's) breath
  • fancy that
  • Fancy that!
  • hear (something) through
  • hear through
  • (have) got something going (with someone)
  • hear from
  • hear from (one)
  • you could hear a pin drop