gadfly vs cleg

gadfly and cleg both are nouns.

Word	Noun	Adjective	Verb	Adverb
gadfly	Yes	No	No	No
cleg	Yes	No	No	No

As nouns, cleg is a hyponym of gadfly; that is, cleg is a word with a more specific, narrower meaning than gadfly:

Other hyponyms of gadfly include botfly, warble fly, clegg, horse fly, horsefly.

gadfly (noun)	cleg (noun)
any of various large flies that annoy livestock	large swift fly the female of which sucks blood of various animals
a persistently annoying person