Sharp Rebuff is a term used to describe a harsh or abrupt rejection. It is often used in the context of a situation where someone has been denied something they asked for, or when someone has been harshly criticized. The crossword solution for Sharp Rebuff is SLAP, which is an appropriate description of the term. A SLAP is a physical gesture that is often used to express disapproval or anger, and it can be seen as a metaphor for a sharp rebuff.