pay off something—
1. pay money owed for smth. in full:
- We have paid off the house only to find that real estate taxes are so high that we cannot afford to keep the house.
2. (Nautical) take a ship out of use, for repair or at the end of her last voyage:
- The decision to pay off the ship came during the last days of her deployment.
pay out something—
1. (of money) pay in small amounts (in settlement of debts, etc.):
- Millions of pounds were being paid out every week in unemployment benefit.
2. allow a rope, etc. to move freely through one’s hands:
- Secure the load in position and pay out enough cable to remove all tension on the cable and drum.