spring chicken vs puppy

spring chicken and puppy both are nouns.

Word	Noun	Adjective	Verb	Adverb
spring chicken	Yes	No	No	No
puppy	Yes	No	No	No

As nouns, puppy is a hyponym of spring chicken; that is, puppy is a word with a more specific, narrower meaning than spring chicken:

Other hyponyms of spring chicken include blade, hobbledehoy, pup, pupil, school-age child, schoolchild, slip.

spring chicken (noun)	puppy (noun)
a young chicken having tender meat	a young dog
a young person (especially a young man or boy)	an inexperienced young person