Grunt

v. snort, make a low gruff sound (like the noise made by hogs); grumble discontentedly

n. snort, low gruff sound (made by hogs and other animals); discontented grumble; foot soldier in the U.S. military (Slang)

The term grunt is slang for an infantryman in the U.S. military and some of the other armed forces of the English speaking world, in both the Army and the Marines. The equipment laden soldiers were said to emit grunting sounds under the weight of modern combat equipment. Originally meant as a disparaging term, infantrymen now take pride in the label. It was coined during the Korean War: "They were called grunts. They were the infantrymen, the foot soldiers of the war" (Bernard Edelman). GRUNT - "Term of affection used to denote that filthy, sweaty, dirt-encrusted, footsore, camouflage-painted, tired, sleepy beautiful little son of a bitch who has kept the wolf away from the door for over two hundred years." -H.G. Duncan Other languages have similarly unflattering slang terms for basic infantry, e.g. Frontschwein in German, bidasse in French or sardo in Spanish.
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Grunt quick, sharp sound created by a forced expiration against a closed glottis; elicited by sharp pain. See also grunting. [more]Grunt - Community and Resources

Noun
1. the short low gruff noise of the kind made by pigs
(hypernym) noise
2. an unskilled or low-ranking soldier or other worker; "infantrymen in Vietnam were called grunts"; "he went from grunt to chairman in six years"
(hypernym) unskilled person
3. medium-sized tropical marine food fishes that utter a grunting sound when caught
(hypernym) percoid fish, percoid, percoidean
(hyponym) margate, Haemulon album
(member-holonym) Haemulidae, family Haemulidae
Verb
1. issue a grunting, low, animal-like noise; "He grunted his reluctant approval"
(hypernym) utter, emit, let out, let loose

v. blossom, sprout and grow; turn green