GRUMP Meaning of GRUMP in English informal■ noun1》 a ~y person. 2》 a fit of sulking. ■ verb act in a sulky, grumbling manner.Derivatives~ish adjective~ishly adverb OriginC18: imitating sounds expressing displeasure. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004