brat vs imp

brat and imp both are nouns.

Word	Noun	Adjective	Verb	Adverb
brat	Yes	No	No	No
imp	Yes	No	No	No

As nouns, imp is a hypernym of brat; that is, imp is a word with a broader meaning than brat:

Other hypernyms of brat include monkey, rapscallion, rascal, scalawag, scallywag, scamp.

brat (noun)	imp (noun)
a very troublesome child	one who is playfully mischievous
a small pork sausage	(folklore) fairies that are somewhat mischievous