Meaning of “square up” - Learner’s Dictionary

square up

phrasal verb with square uk us /skweər/ verb

to prepare to fight, compete, or argue with someone:

The players squared up to each other and started shouting.
PAY informal

to pay someone the money that you owe them:

If you pay for it now, I'll square up with you later.

(Definition of “square up” from the Cambridge Learner’s Dictionary © Cambridge University Press)