Actions with the flourish trait are special techniques that require too much exertion for you to perform frequently. You can use only one action with the flourish trait per round.
Rogue
This indicates abilities from the rogue class.
Source: Player Core pg. 176
You leap from hiding and assail your target. You Stride up to your Speed, but you must end your movement next to an enemy you’re hidden from or undetected by. You then Strike that enemy; you remain hidden from or undetected by that creature until after you Strike. You can use Spring from the Shadows while Burrowing, Climbing, Flying, or Swimming instead of Striding if you have the corresponding movement type.