father-in-law vs male parent

father-in-law and male parent both are nouns.

Word	Noun	Adjective	Verb	Adverb
father-in-law	Yes	No	No	No
male parent	Yes	No	No	No

As nouns, male parent is a hypernym of father-in-law; that is, male parent is a word with a broader meaning than father-in-law:

Other hypernyms of father-in-law include begetter, father, in-law, relative-in-law.

father-in-law (noun)	male parent (noun)
the father of your spouse	a male parent (also used as a term of address to your father)