What is the term for a blunt or abrupt repulse or refusal?

The term "rebuff" specifically denotes a situation where someone is met with a blunt or abrupt refusal. It carries a connotation of a strong or dismissive setback that often implies a degree of rudeness or abruptness in the response. This term captures not just the act of refusal but also the manner in which it is delivered—firm and often unexpected.

In contrast, the other terms like "reject," "dismiss," and "refuse" can describe a general refusal or denial but lack the particular nuance of a brusque interaction inherent in "rebuff." "Reject" means to refuse to accept something, "dismiss" implies a rejection based on a lack of consideration or importance, and "refuse" indicates a straightforward denial but doesn't convey the abruptness that "rebuff" does. Thus, the appropriateness of "rebuff" in describing a blunt refusal is what makes it the correct choice.