flightless bird vs ratite

flightless bird and ratite both are nouns.

Word	Noun	Adjective	Verb	Adverb
flightless bird	Yes	No	No	No
ratite	Yes	No	No	No

As nouns, flightless bird and ratite are synonyms defined as:

flightless bird and ratite: flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches, cassowaries, emus, moas, rheas, kiwis, elephant birds

Other synonyms of flightless bird include ratite bird.

flightless bird (noun)	ratite (noun)
flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches, cassowaries, emus, moas, rheas, kiwis, elephant birds	flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches, cassowaries, emus, moas, rheas, kiwis, elephant birds