/ grʌf; NAmE / adjective
1.
( of a voice ) deep and rough, and often sounding unfriendly
2.
( of a person's behaviour ) unfriendly and impatient :
Beneath his gruff exterior, he's really very kind-hearted.
► gruff·ly adverb
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WORD ORIGIN
late 15th cent. (in the sense coarse-grained ): from Flemish and Dutch grof coarse, rude, of West Germanic origin.