n. & v.
n. 1 a low guttural sound made by a pig. 2 a sound resembling this. 3 any fish of the genus Haemulon that grunts when caught.
v. 1 intr. (of a pig) make a grunt or grunts. 2 intr. (of a person) make a low inarticulate sound resembling this, esp. to express discontent, dissent, fatigue, etc. 3 tr. utter with a grunt.
[ OE grunnettan, prob. orig. imit. ]