A grunt can refer to several things, including:

• Animal sound: A grunt is a short, low sound that an animal, such as a pig, makes.

• Military personnel: In the military, a grunt is a term used to refer to a foot soldier, especially in the Vietnam War.

• Food fish: A grunt is also a type of food fish found in tropical and subtropical seas that emits grunting sounds.

• Verb: To grunt means to issue a grunting, low, animal-like noise.

In summary, a grunt can refer to an animal sound, a type of food fish, a military personnel, or a verb meaning to issue a grunting noise.