animal skin vs lambskin

animal skin and lambskin both are nouns.

Word	Noun	Adjective	Verb	Adverb
animal skin	Yes	No	No	No
lambskin	Yes	No	No	No

As nouns, lambskin is a hyponym of animal skin; that is, lambskin is a word with a more specific, narrower meaning than animal skin:

Other hyponyms of animal skin include parchment, sheepskin, fell, hide, leather, fur, pelt.

animal skin (noun)	lambskin (noun)
the outer covering of an animal	the skin of a lamb with the wool still on
	skin of a sheep or goat prepared for writing on