flycatcher vs pewit

flycatcher and pewit both are nouns.

Word	Noun	Adjective	Verb	Adverb
flycatcher	Yes	No	No	No
pewit	Yes	No	No	No

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

flycatcher: large American birds that characteristically catch insects on the wing
pewit: small olive-colored woodland flycatchers of eastern North America

flycatcher (noun)	pewit (noun)
any of a large group of small songbirds that feed on insects taken on the wing	large crested Old World plover having wattles and spurs
large American birds that characteristically catch insects on the wing	small olive-colored woodland flycatchers of eastern North America
	small black-headed European gull