Meaning of 早口 - fast talker WaniKani and Jisho.org give the definition of {} as "fast talker". In English, this can have several shades of meaning. Which of the following (or others) apply in Japanese: * someone who speaks rapidly: _she's such a fast talker I can't understand a word she says_ * a salesman or con-artist; they talk so fast you can't keep up and you end up agreeing to something you're not quite sure of: _A fast talking salesman who could sell a freezer to an Eskimo_ * someone who can get out of tricky situations. _He's such a fast talker he always gets in trouble but rarely suffers the consequences._ WaniKani also suggests it might mean _motor-mouth_ , as in someone who talks and talks and won't shut up.

is a noun or no-/na-adjective that just means "talking rapidly". To use it adverbially, and are both okay. Among the three bullets you gave, covers only the first one. It doesn't mean someone won't shut up, either.

To describe a fast-talking salesman, is a set phrase that has a mild negative connotation. is equally common and negative.