Deber is a Spanish verb that can be translated into English as "to owe," "should," or "ought." It is used to express obligation, duty, or moral responsibility. In different contexts, it can convey different levels of obligation or necessity. For example, "deber" can be used to indicate that someone owes money or a favor to someone else. It can also be used to express what someone should or ought to do in terms of their responsibilities or moral obligations.