Where does “sellout” come from?

sellout (Breton) comes from Middle Breton sellet, from Arabic سَلَتَ.

sellout (Breton): to watch; to look at

Definitions

Step	Language	Word	Meaning
1	Middle Breton	sellet	—
2	Arabic	سَلَتَ	—

sellout — Etymology, Origin & Word History | Etymology Explorer