finger alphabet vs manual alphabet

finger alphabet and manual alphabet both are nouns.

Word	Noun	Adjective	Verb	Adverb
finger alphabet	Yes	No	No	No
manual alphabet	Yes	No	No	No

As nouns, finger alphabet and manual alphabet are synonyms defined as:

finger alphabet and manual alphabet: an alphabet used by the deaf; letters are represented by finger positions

finger alphabet (noun)	manual alphabet (noun)
an alphabet used by the deaf; letters are represented by finger positions	an alphabet used by the deaf; letters are represented by finger positions