1. a forceful and bitter verbal attack against someone or something:"a diatribe against consumerism"
Word Originlate 16th century (denoting a disquisition): from French, via Latin from Greek diatribē ‘spending of time, discourse’, from dia ‘through’ + tribein ‘rub’.
A diatribe, also known less formally as rant, is a lengthy oration, though often reduced to writing, made in criticism of someone or something, often employing humor, sarcasm, and appeals to emotion. Wikipedia