IPA: /prəˈmɪzər/
KK: /prəˈmɪsər/
A person or entity that makes a promise to do something or to provide something in the future.
In the contract, the promisor agreed to deliver the goods by the end of the month.
Promisor → It is formed from "pro-" (meaning for or in favor of) and "mittere" (meaning to send). The word refers to someone who sends forth a promise or commitment.
Think of someone 'sending forth' ('mittere') a commitment or assurance 'for' ('pro-') another person — that's what a promisor does.