newborn vs new-sprung

newborn is a noun but new-sprung is not a noun.

Word	Noun	Adjective	Verb	Adverb
newborn	Yes	Yes	No	No
new-sprung	No	Yes	No	No

As adjectives, newborn and new-sprung are synonyms defined as:

newborn and new-sprung: having just or recently arisen or come into existence

newborn (noun)	new-sprung (noun)
a baby from birth to four weeks

newborn (adjective)	new-sprung (adjective)
having just or recently arisen or come into existence	having just or recently arisen or come into existence
recently born