pixie vs brownie

pixie and brownie both are nouns.

Word	Noun	Adjective	Verb	Adverb
pixie	Yes	No	No	No
brownie	Yes	No	No	No

As nouns, pixie and brownie are synonyms defined as:

Other synonyms of pixie include elf, gremlin, hob, imp, pixy.

pixie (noun)	brownie (noun)
(folklore) fairies that are somewhat mischievous	square or bar of very rich chocolate cake usually with nuts
creeping evergreen shrub having narrow overlapping leaves and early white star-shaped flowers; of the pine barrens of New Jersey and the Carolinas	(folklore) fairies that are somewhat mischievous