Hilchos Lashon Hara, chapter 1, section 3

A person who speaks badly about others once in a while breaks "Do not go as a talebearer in your nation."

But if, Heaven forbid, he does this sin all the time as a habit - like people who sit and talk badly about others - Chazal call them "ba'alei lashon hara" (habitual speakers of lashon hara). Their punishment is much greater, because they break Hashem's Torah out of contempt for it and treat the prohibition as nothing. About them it says in Tehillim (12:4), "Hashem will cut off all flattering lips, a tongue that speaks proud things."