A hurdle rate is the threshold return below which GPs receive no carry. Common hurdles range from 6% to 10% per year. Below the hurdle, all profits go to LPs; above the hurdle, GPs typically catch up to their full carry percentage and then split additional profits per the agreed waterfall.
Hurdles are common in private equity and growth funds; they're less common in early-stage venture, where the long J-curve and high variance make a meaningful hurdle hard to enforce. Many top venture funds operate without a hurdle.