Definition of "grunt"

The stranger, with a comfortable kind of grunt over his pipe, put his legs up on the settle that he had to himself.

1861, Charles Dickens, Great Expectations, Chapter X

The poges stare at the grunts as though the grunts were Hell's Angels at the ballet.

1979, Gustav Hasford, The Short-Timers, New York: Bantam Books, published 1980, page 39

The events described are those encountered by only 160 men, though the adversity recounted is representative of that experienced by all grunts in Vietnam.

1984, Charles Robert Anderson, The Grunts, Berkley Books, page xii

He can't make that kind of decision. He's just a grunt!

1986, James Cameron, Aliens, spoken by Burke (Paul Reiser)

The engine might not possess quite as much grunt as the later 24v six, but it delivers invigorating performance […]

1992, Autocar & Motor, volume 192, page 61

With this much grunt, it is surprising that the engine is relatively quiet.

2006 February, Torque, page 56

The lack of bottom-end grunt presents as a particular problem in hilly terrain where the five-speed manual gearbox really earns its keep.

2021 February, The Road Ahead, Brisbane, page 55, column 2

to grunt and sweat under a weary life

c. 1599–1602 (date written), William Shakespeare, “The Tragedie of Hamlet, Prince of Denmarke”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act III, scene i]

The silhouette sharpens and fades as the carving is moved before the flames of the hearth, its maker grunts in perfect imitation of the ancestor - a human-lioness in oestrus.

2018, Tim Flannery, Europe: A Natural History, page 186