maleness vs gender

maleness and gender both are nouns.

Word	Noun	Adjective	Verb	Adverb
maleness	Yes	No	No	No
gender	Yes	No	No	No

As nouns, gender is a hypernym of maleness; that is, gender is a word with a broader meaning than maleness:

maleness: the properties characteristic of the male sex
gender: the properties that distinguish organisms on the basis of their reproductive roles

Other hypernyms of maleness include sex, sexuality.

maleness (noun)	gender (noun)
the properties characteristic of the male sex	the properties that distinguish organisms on the basis of their reproductive roles
	a grammatical category in inflected languages governing the agreement between nouns and pronouns and adjectives; in some languages it is quite arbitrary but in Indo-European languages it is usually based on sex or animateness