pes vs splayfoot

pes and splayfoot both are nouns.

Word	Noun	Adjective	Verb	Adverb
pes	Yes	No	No	No
splayfoot	Yes	Yes	No	No

As nouns, splayfoot is a hyponym of pes; that is, splayfoot is a word with a more specific, narrower meaning than pes:

pes: the part of the leg of a human being below the ankle joint
splayfoot: a foot afflicted with a fallen arch; abnormally flattened and spread out

Other hyponyms of pes include flatfoot, pes planus.

pes (noun)	splayfoot (noun)
the part of the leg of a human being below the ankle joint	a foot afflicted with a fallen arch; abnormally flattened and spread out

pes (adjective)	splayfoot (adjective)
	having feet that turn outward