gruff adj.

1530s, of physical things, "coarse, coarse-grained," from Middle Dutch or Middle Low German grof "coarse (in quality), thick, large," of uncertain origin, regarded by some as related to Old English hreof, Old Norse hrjufr "rough, scabby," with Germanic completive prefix ga-. Of manners, "rough, surly," by 1690s. Related: Gruffness.