The term "had better" is often used to imply that it's advisable or necessary for someone to do something. It can also be interpreted as a warning or a recommendation for the sake of someone's well-being or self-interest. Some synonyms for "had better" include "should," "ought to," "need to," "must," "have to," "be obliged to," "be required to," and "would be wise to." These phrases all communicate a level of urgency and importance, conveying a sense of responsibility or duty to take action. Ultimately, using any of these synonyms forces the speaker to communicate a clear message of what they expect from the listener.