A promise that pledges nothing, because it is vague or because the promisor can choose whether or not to honor it. Such promises are not legally binding. For example, if you get a new job and promise to work for three years, unless you resign sooner, you haven't made a valid contract and can resign or be fired at any time. As consultants we've seen many of these amongst grooming business owners. Don't just talk agreements, have them written by a professional and use them properly to avoid misunderstandings and disruption.