noun
Rare term for skillful, persuasive speech. More common synonyms are 雄弁 (ゆうべん) or 能弁 (のうべん).
彼の口弁は聴衆を魅了した。
His eloquence captivated the audience.
Compound of 口 (mouth, speech) and 弁 (speech, dialect). The exact historical derivation is uncertain.