The verb form of the word "mulled" means to steep or soak something in a liquid, often hot, for an extended period of time. This process can be used with various materials such as spices, fruits, and herbs to release their flavors into another substance like wine, cider, or water. The resulting mixture is then called "mulled" when it has been prepared in this way.
In a more general sense, the term "mulled" can also refer to something that has been carefully considered or deliberated upon, often with multiple viewpoints taken into account before making a decision. This usage of the word is less common and typically used in formal settings such as politics or business.