grunt

Concise Oxford English Dictionary © 2008 Oxford University Press:
grunt/ɡrʌnt/

▶verb

• 1 (of an animal, especially a pig) make a low, short guttural sound.

• 2 make a low inarticulate sound to express effort or indicate assent.

▶noun

• 1 a grunting sound.

• 2 N. Amer. informal a low-ranking soldier or unskilled worker.

• 3 Brit. informal power, especially in a motor vehicle.

• 4 an edible fish of tropical coasts and reefs, able to make a loud noise. [Family Pomadasyidae: many species.]

– derivatives
grunter noun.

– origin OE grunnettan, of Gmc origin.