An offer is a proposal from one party to another intending to create a legal obligation upon acceptance. In New Jersey, a legal definition of a contract has very definite terms.An offer is a written or verbal promise to undertake some obligation. There are several elements that go into making an offer enforceable under NJ contract law. For a valid contract to exist, there must be offer and acceptance. Offer: A proposal to enter into a contract. Acceptance: An agreement to enter into a contract on the terms offered. Under English law, an offer at its most basic level is simply a proposal to enter into an agreement.