What does 陰口 mean?
陰口 is a Japanese noun meaning “malicious gossip; backbiting; speaking ill behind someone's back” in English. It is written as 陰口 in kanji, かげぐち in hiragana, and kageguchi in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
だれか人に、言い分があったら、陰口をいわないで、その人に面と向かっていいなさい。
If you have a bone to pick with a person, tell it to his face instead of saying things behind his back.