signer vs signatory

signer and signatory both are nouns.

Word	Noun	Adjective	Verb	Adverb
signer	Yes	No	No	No
signatory	Yes	No	No	No

As nouns, signer and signatory are synonyms defined as:

signer (noun)	signatory (noun)
someone who signs and is bound by a document	someone who signs and is bound by a document
someone who can use sign language to communicate