Old World flycatcher vs true flycatcher

Old World flycatcher and true flycatcher both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old World flycatcher	Yes	No	No	No
true flycatcher	Yes	No	No	No

As nouns, Old World flycatcher and true flycatcher are synonyms defined as:

Old World flycatcher and true flycatcher: any of a large group of small songbirds that feed on insects taken on the wing

Other synonyms of Old World flycatcher include flycatcher.

Old World flycatcher (noun)	true flycatcher (noun)
any of a large group of small songbirds that feed on insects taken on the wing	any of a large group of small songbirds that feed on insects taken on the wing