A promisor is someone who makes a promise to a promisee.
Contract law teaches us whether the promisor is legally obligated to keep his promise.
For example, if Mr. A promises to pay Mr. B $500 then A is the promisor and B is the promisee. Contract law informs us whether Mr. A is liable if he breaks his promise.
Consider the following example: Mr. A promises to pay Mr. B $500 and Mr. B says, “Great! Now I can get that tablet computer I always wanted.” Is A in legal trouble if he decides not to pay? Contract law tells us whether the promisor must keep his promise.
Often, you will see more than one promise being made. A person can be both a promisor and a promisee if he exchanges promises with the other party. For example, if Mr. A promises to sell his car for $1,000 and Mr. B promises to pay $1,000 when the car is delivered, Mr. A is both a promisor and a promisee because Mr. A and Mr. B made promises to each other. Be careful, and don’t lose track of who is the promisor and who is the promisee with respect to each promise.