calf vs leather

calf and leather both are nouns.

Word	Noun	Adjective	Verb	Adverb
calf	Yes	No	No	No
leather	Yes	No	Yes	No

As nouns, leather is a hypernym of calf; that is, leather is a word with a broader meaning than calf:

calf: fine leather from the skin of a calf
leather: an animal skin made smooth and flexible by removing the hair and then tanning

calf (noun)	leather (noun)
young of domestic cattle	an animal skin made smooth and flexible by removing the hair and then tanning
young of various large placental mammals e.g. whale or giraffe or elephant or buffalo
the muscular back part of the shank
fine leather from the skin of a calf

calf (verb)	leather (verb)
	whip with a leather strap