When someone calls it quits it means to stop doing something.
To give up especially after applying oneself to it for a certain length of time.
To quit; to resign from something; abandon something.
1. Star athletes often retire early and call it quits.
2. After 5 years of marriage, Richard and Helen have called it quits.
3. It’s been raining all day, maybe we should call it quits.
4. The three-time Olympian called it quits after much controversy over his doping test.
abandon, break off, cease, conclude, desist, discontinue, drop, end, give notice, give up, halt, hang it up, leave, let go, part with, put an end to, resign, retire, stop, suspend, terminate, throw in the towel, withdraw, wrap up