grumpy vs bad-tempered

grumpy and bad-tempered both are adjectives.

Word	Noun	Adjective	Verb	Adverb
grumpy	No	Yes	No	No
bad-tempered	No	Yes	No	No

As adjectives, grumpy and bad-tempered are synonyms defined as:

Other synonyms of grumpy include crabbed, crabby, cross, fussy, grouchy, ill-tempered.

grumpy (adjective)	bad-tempered (adjective)
annoyed and irritable	annoyed and irritable