motormouth
mo·tor·mouth
noun
1.
Origin
From motor + mouth, from the figurative notion that the mouth moves so much that it seems motorized.
Related words
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.