Which word refers to a severe and often abusive criticism?

The term that refers to a severe and often abusive criticism is "diatribe." A diatribe is typically a forceful and bitter verbal attack against someone or something. It often includes strong language and is delivered with a sense of urgency and passion, indicating the speaker’s strong feelings about the subject of criticism. This aligns perfectly with the concept of severe and abusive criticism, as a diatribe is meant to express deep dissatisfaction, anger, or contempt, often directed at a person's actions or beliefs.

Conversely, the other options do not carry this meaning. "Desultory" describes something that lacks a plan or purpose and is usually associated with disconnected or random behavior, rather than criticism. "Dichotomy" refers to a division into two contrasting parts or categories, typically used in discussions about classification rather than in the context of criticism. "Diffident" pertains to shyness or a lack of self-confidence, indicating a person who may be hesitant to express criticism rather than one who delivers it forcefully. Therefore, the suitability of "diatribe" as a descriptor for severe and abusive criticism is clear and well-founded.