The term "bigmouth" typically refers to someone who talks excessively or boastfully. There are a number of synonyms that can be used to describe such a person. For example, one might call them a blabbermouth, a windbag, or a chatterbox. These terms all conjure up the image of someone who simply cannot keep quiet or resist the urge to brag about their achievements or opinions. Other possible synonyms for bigmouth might include show-off, bragger, or blowhard. Whatever term is used, it is clear that a bigmouth is someone who can be irritating or frustrating to deal with, especially when they refuse to let others get a word in edgewise.