1.
If you pay off a debt, you give someone all the money that you owe them.
It would take him the rest of his life to pay off that loan.
PHRASAL VERB : V P n (not pron) , also V n P
2.
If you pay off someone, you give them the amount of money that you owe them or that they are asking for, so that they will not take action against you or cause you any trouble.
...his bid to raise funds to pay off his creditors...
PHRASAL VERB : V P n (not pron) , also V n P
3.
If an action pays off , it is successful or profitable after a period of time.
Sandra was determined to become a doctor and her persistence paid off.
PHRASAL VERB : V P
4.
see also payoff