Middle English word watir edyr comes from Old English nædre (Snake, serpent.), Old English wæter (Water.)

Detailed word origin of watir edyr

Dictionary entry	Language	Definition
nædre	Old English (ang)	Snake, serpent.
wæter	Old English (ang)	Water.
wæternǣdre	Old English (ang)
watyrnedyre	Middle English (enm)

Words with the same origin as watir edyr