Middle English word forgan comes from Old English fore-, Old English gān, Old English gan (To go.)

Detailed word origin of forgan

Dictionary entry	Language	Definition
fore-	Old English (ang)	Before, in front of, pro-. First, prime, occupying a prominent position. Very, supremely, foremost.
gān	Old English (ang)
gan	Old English (ang)	To go.
foregān	Old English (ang)
foregan	Old English (ang)	To precede, stand out, go before; forego.
forgan	Middle English (enm)

Words with the same origin as forgan