father-in-law vs father

father-in-law and father both are nouns.

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

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

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

father-in-law (noun)	father (noun)
the father of your spouse	a male parent (also used as a term of address to your father)
	the founder of a family
	a person who holds an important or distinguished position in some organization
	a person who founds or establishes some institution
	the head of an organized crime family

father-in-law (verb)	father (verb)
	make (offspring) by reproduction