Where does “ruddy” come from?

ruddy (Middle English) comes from Old English rudiġ, from Old English -iġ, from Proto-West Germanic -g, from Proto-Germanic -gaz, from Proto-Indo-European -ḱos — -y, -ic.

Ancestry of “ruddy”, step by step

Step	Language	Word	Meaning
1	Old English	rudiġ	reddish; ruddy
2	Old English	-iġ	-y, -ic
3	Proto-West Germanic	-g	Forms adjectives from nouns and verbs with a...
4	Proto-Germanic	-gaz	-y
5	Proto-Indo-European	-ḱos	-y, -ic

Every word from Proto-Indo-European -ḱos →Every word from Old English -iġ →Every word from Proto-Germanic -gaz →