signor vs. signer

noun

plural

signors 
,

plural

signori .
  1. a conventional Italian term of address or title of respect for a man, either used separately or prefixed to the name. Sig., sig.

noun

  1. a person who signs.

  2. a person who writes their name, as in token of agreement.

  3. a person who communicates by or interprets into sign language.