To express at length a complaint or negative opinion:
To speak or say quickly, incoherently, or nonsensically; chatter; gibber
To discharge (a flowing or spurting liquid); release:
To talk on something exceedingly long, annoying the audience.
To rave is defined as to speak or move violently or wildly, particularly in appreciation of something.
Find another word for mouth-off. In this page you can discover 5 synonyms, antonyms, idiomatic expressions, and related words for mouth-off, like: rant, jabber, spout, rabbit-on and rave.