Middle English word swapen comes from Proto-Indo-European *ksweybʰ-, and later Proto-Germanic *swaipaną (To cast, fling. To sway, swing. To sweep. To wrap.)

Detailed word origin of swapen

Dictionary entry	Language	Definition
*ksweybʰ-	Proto-Indo-European (ine-pro)
*swaipaną	Proto-Germanic (gem-pro)	To cast, fling. To sway, swing. To sweep. To wrap.
swāpan	Old English (ang)
swapen	Middle English (enm)

Words with the same origin as swapen