Where does “won't” come from?

won't (English) comes from English wonnot, from Middle English wolnot, from Middle English will not.

won't (English): will not

Definitions

Step	Language	Word	Meaning
1	English	wonnot	—
2	Middle English	wolnot	—
3	Middle English	will not	—

won't — Etymology, Origin & Word History | Etymology Explorer