Quit definition

From , , from .

To pay (a debt, fine etc.).
To repay, pay back (a good deed, injury etc.).
- 1485, Sir Thomas Malory, Le Morte Darthur, Book II:
  
  twyes smote I hym doune, & thenne he promysed to quyte me on my best frynde, and so he wounded my sone [...].
To conduct oneself, acquit oneself, to behave (in a specified way).
To abandon, renounce (a thing).
To leave (a place).
To resign from (a job, office, position, etc.).
To stop, give up (an activity) (usually + gerund or verbal noun).

John is planning to quit smoking.
To close (an application).

The past tense of quit is now quit for most speakers and writers; dictionaries usually allow quitted as an alternative, but it is rare or nonexistent in North America and Australia, and outnumbered by quit by about 16 to 1 in the British National Corpus. Quitted is more commonly used to mean "left". ie. She quitted her job.