male parent vs pappa

male parent and pappa both are nouns.

Word	Noun	Adjective	Verb	Adverb
male parent	Yes	No	No	No
pappa	Yes	No	No	No

As nouns, pappa is a hyponym of male parent; that is, pappa is a word with a more specific, narrower meaning than male parent:

Other hyponyms of male parent include dad, dada, daddy, pa, papa, pop, father-in-law, old man, pater.

male parent (noun)	pappa (noun)
a male parent (also used as a term of address to your father)	an informal term for a father; probably derived from baby talk