nipper vs yearling

nipper and yearling both are nouns.

Word	Noun	Adjective	Verb	Adverb
nipper	Yes	No	No	No
yearling	Yes	No	No	No

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

nipper (noun)	yearling (noun)
a grasping structure on the limb of a crustacean or other arthropods	an animal in its second year
a young person of either sex	a racehorse considered one year old until the second Jan. 1 following its birth
	a young child who is just beginning to walk