Middle English word redy comes from Proto-Indo-European *rīdʰ-, and later Proto-Germanic *raidaz (Ready, arranged, prepared.)

Detailed word origin of redy

Dictionary entry	Language	Definition
*rīdʰ-	Proto-Indo-European (ine-pro)
*raidaz	Proto-Germanic (gem-pro)	Ready, arranged, prepared.
ræde	Old English (ang)	Ready, prompt, prepared; ready to ride, mounted (on a horse). Simple, plain. Skilled.
ired	Middle English (enm)

Words with the same origin as redy