spurious wing vs bastard wing

spurious wing and bastard wing both are nouns.

Word	Noun	Adjective	Verb	Adverb
spurious wing	Yes	No	No	No
bastard wing	Yes	No	No	No

As nouns, spurious wing and bastard wing are synonyms defined as:

spurious wing and bastard wing: tuft of small stiff feathers on the first digit of a bird's wing

Other synonyms of spurious wing include alula.

spurious wing (noun)	bastard wing (noun)
tuft of small stiff feathers on the first digit of a bird's wing	tuft of small stiff feathers on the first digit of a bird's wing