振振有詞 [－－－词]

Jyutping zan3 zan3 jau5 ci4
Pinyin zhèn zhèn yǒu cí

Definitions (CC-CEDICT)
  1. to speak forcefully and with justice (idiom); to argue with the courage of one's convictions
Definitions (粵典–words.hk)
  1. 動詞
    深信​自己​有​充分​嘅​理​據​，​好​有​自信​咁​向​其他人​講​嘢
    to speak with complete confidence in oneself
Definitions (Wiktionary)
  1. phrase, idiomatic
    to speak plausibly and at length
Definitions (Kaifangcidian)
  1. （沒有對應漢語詞彙）