Big Mouth is often used to describe a person who talks excessively and can't keep a secret. Some possible synonyms for Big Mouth are blabbermouth, chatterbox, gossiper, loudmouth, blowhard, windbag, or motor-mouth. Other variations that could be used include loose lips, gabber, mouthpiece, chatterer, tattletale, or yapper. These all describe an individual who tends to gossip or talk without thinking before speaking. It is essential to choose words that are polite and not offensive when describing someone's behavior, and it is better to address an individual's actions rather than labeling them with a derogatory term.