manful vs masculine

manful is not a noun while masculine is a noun.

Word	Noun	Adjective	Verb	Adverb
manful	No	Yes	No	No
masculine	Yes	Yes	No	No

manful (noun)	masculine (noun)
	a gender that refers chiefly (but not exclusively) to males or to objects classified as male

manful (adjective)	masculine (adjective)
possessing qualities befitting a man	associated with men and not with women
characteristic of a man	male (of grammatical gender)
	(music or poetry) ending on an accented beat or syllable