youth vs pup

youth and pup both are nouns.

Word	Noun	Adjective	Verb	Adverb
youth	Yes	No	No	No
pup	Yes	No	Yes	No

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

Other hyponyms of youth include blade, hobbledehoy, puppy, pupil, school-age child, schoolchild, slip.

youth (noun)	pup (noun)
the freshness and vitality characteristic of a young person	young of any of various canines such as a dog or wolf
young people collectively	an inexperienced young person
a young person (especially a young man or boy)
early maturity; the state of being young or immature or inexperienced
the time of life between childhood and maturity
an early period of development

youth (verb)	pup (verb)
	give birth to (a puppy)