A diatribe is a long, angry attack in speech or writing. You are not calmly disagreeing; you keep going, and you hit hard. A newspaper column can be a diatribe against a leader. A tired parent can go into a diatribe about mess in the kitchen. It feels a bit formal and a bit literary; in everyday talk people often say rant instead. You usually hear a diatribe against someone or something. Though actually, the word did not start out angry. English borrowed it from French in the late 1500s. Behind that sits Latin diatriba, a learned discussion, and behind that a Greek word about spending time — sitting with an idea and talking it through. The bitter, one-sided meaning grew later. So the tidy picture “angry speech” is how we use it now, but the older life of the word was closer to a long talk.