1778, from grump + -y (2). Related: Grumpily; grumpiness. Scottish variant grumphie also was used as a generic name for a pig.
Entries linking to grumpy
grump n.
"ill-humor," 1727, in humps and grumps "surly remarks," later the grumps "a fit of ill-humor" (1844), then "a person in ill humor" (1900); perhaps an extended sense of grum "morose, surly," which probably is related to Danish grum "cruel;" or perhaps suggested by grumble, grunt, etc.
-y 2
adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.