What it does
Sharpness multiplies the power of slicing moves by 1.5. Slicing moves are those with the slicing flag: Leaf Blade, Night Slash, Sacred Sword, Psycho Cut, Razor Shell, Air Slash, Cross Poison, Ceaseless Edge, Slash, and more. The flag is on the move, not the type — Sacred Sword is Fighting-type but slicing, Aerial Ace is Flying-type but not slicing.
The numbers: Leaf Blade goes from 90 to effectively 135. Night Slash from 70 to 105. Sacred Sword from 90 to 135, and it already ignores the target's Defense boosts on top of that. Psycho Cut hits 105 as well. That's not a situational bonus — it's a blanket upgrade across the entire moveset.
Who runs it
Gallade runs Sharpness at 98% usage and the reason is obvious — nearly its entire competitive moveset consists of slicing moves. Psychic/Fighting typing with 125 base Attack, and Leaf Blade, Night Slash, Sacred Sword, Psycho Cut all get the 1.5x. You're not choosing between coverage and staying on-ability. You get both at once.
Kleavor uses it at 92%. Bug/Rock type with Stone Axe — a slicing move that sets Stealth Rock on the target's side on contact — and X-Scissor also benefiting. The damage boost and the entry hazard threat together make it a solid disruptive attacker, especially in singles where Stealth Rock does sustained work.
How to use it
Gallade's gameplay is straightforward: pick the right slicing move for the matchup and hit hard. Sacred Sword into anything that has stacked Defense boosts — Sharpness makes it hurt even without ignoring the boosts being fully counted. Leaf Blade for Water and Ground types. Night Slash for Psychic-immune targets. Psycho Cut into Fighting-weak targets.
Base 80 Speed is the weak point. You'll want a +Speed nature with full EVs, or play it in a Trick Room team where the Speed becomes an advantage.
Tips & strategy
Sacred Sword plus Sharpness is the specific answer to stall and defensive setup. It ignores Defense boosts AND hits at 135 effective power — a Blissey or something that has used Iron Defense twice gets hit as if those boosts don't exist, and the raw damage is still high. That combination is rare and genuinely threatening.
Night Slash gets a high-crit-rate boost on top of the power. Critical hits ignore the target's Defense boosts, so there's overlap with Sacred Sword's niche, but the extra crit chance means you can occasionally blow through calculations on regular defensive targets too.
Close Combat is not a slicing move, so it gets no boost from Sharpness. Use it when you specifically need the raw Fighting coverage, not as a go-to. The slicing moves are almost always the stronger play.