Grumble/ˈɡrʌmbl/ Definition 1 of 3Pro Tip 1/3Subtle discontent Used to indicate a mild or repressed annoyance without confrontation. She grumbled about the cold office but didn't request a heater. Pro Tip 2/3Not Directly Expressing complaints indirectly, without addressing someone specifically. Walking away from the meeting, Jonah grumbled about the decision. Pro Tip 3/3Low Volume Grumbling is not loud; it's quiet and may not be fully audible to others. He grumbled to himself about the homework load.