It seems opposite is a merger of two concepts, a spatial oppositum and a temporal oppausatum, each from pone put and pausa stop. The spatial opposite should be known as the complement and the temporal opposite as the numerical complement. The numerical complement nullifies (as in positive and negative mass, rather than annihilates as in positive and negative charge) properties whereas the complement makes a finite set.
So a woman or mulier is a sex, rather than wif or femina the gender, whereas man is a species (a being with a mind), whereas wapman or mas is a sex and wer or vir the gender. They can't be compared to each other. Woman and wapman are complementary, not opposite; the opposite of a woman is a hýpothetic being that wrecks wombs, ovaries, and XX organelles. (One in negative mass likely can't be constructed as then like charges and quarks attract each other into unique elements. One in antimatter could work but it'd destroy anyone. One in heterokiral molecules couldn't in itself wreck a usual woman but this could be considered a complement or spatial opposite. Nucleic acids of complementary kirality can't metavolize or breed with each other.) Likewise the complement of a man is a deer or elf or troll, dependent on scale. Related to the complement and opp[au]site is the privative, that which makes none, and the negative, that which is the oppausite, and the alternative, that which is the complement. So the privative of a man could be ebola or necrotizing fasciitis, the negative of a man some anencefaly, and the alternative of a man some ape or fossil, at scales different to aforesaid.