leprechaun vs gremlin

leprechaun and gremlin both are nouns.

Word	Noun	Adjective	Verb	Adverb
leprechaun	Yes	No	No	No
gremlin	Yes	No	No	No

As nouns, gremlin is a hypernym of leprechaun; that is, gremlin is a word with a broader meaning than leprechaun:

Other hypernyms of leprechaun include brownie, elf, hob, imp, pixie, pixy.

leprechaun (noun)	gremlin (noun)
a mischievous elf in Irish folklore	(folklore) fairies that are somewhat mischievous