mid-15c., a legal principle, "restoration of a prior or more valid title to certain property," from Old French remitter, noun use of infinitive, from Latin remittere "send back" (see remit). For legalese noun use of French infinitives, see waiver.
late 14c., remitten, "to forgive, pardon," from Latin remittere "send back, slacken, let go back, abate," from re- "back" (see re-) + mittere "to send" (see mission). Secondary senses predominate in English.
From c. 1400 as "refer for consideration or performance from one person or group to another;" early 15c. as "send to prison or back to prison." The meaning "allow to remain unpaid, refrain from exacting" (penalty, punishment, etc.) is from mid-15c. Meaning "send money (to someone) in payment" is recorded from 1630s. Related: Remitted; remitting.
"act of waiving," 1620s (modern usage is often short for waiver clause); from Anglo-French legal usage of infinitive as a noun (see waive). Baseball waivers is recorded from 1907. Other survivals of noun use of infinitives in Anglo-French legalese include disclaimer, merger, rejoinder, misnomer, ouster, retainer, attainder.
<a href="https://www.etymonline.com/word/remitter">Etymology of remitter by etymonline</a>
Harper, D. (n.d.). Etymology of remitter. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/remitter