predic.adj. on even terms by retaliation or repayment (then we'll be quits). call it (or cry) quits acknowledge that things are now even; agree not to proceed further in a quarrel etc.
[ perh. colloq. abbr. of med.L quittus: see QUIT ]
QUITS
Meaning of QUITS in English
Concise Oxford English dictionary. Краткий оксфордский словарь английского языка. 2012