The Collaborative International Dictionary of English v.0.48:
loud-mouth \loud-mouth\ n. 1. a person who causes trouble by speaking indiscretely. [WordNet sense 1] Syn: loudmouth, blusterer. [WordNet 1.5] 2. Aperson who is loud-mouthed. [PJC]WordNet (r) 3.0 (2006):
loudmouth n 1: a person who causes trouble by speaking indiscreetly [syn: loudmouth, blusterer]