signor vs signior

signor and signior both are nouns.

Word	Noun	Adjective	Verb	Adverb
signor	Yes	No	No	No
signior	Yes	No	No	No

As nouns, signor and signior are synonyms defined as:

signor and signior: used as an Italian courtesy title; can be prefixed to the name or used separately

signor (noun)	signior (noun)
used as an Italian courtesy title; can be prefixed to the name or used separately	used as an Italian courtesy title; can be prefixed to the name or used separately