I was taught that:-
- 'man(n)' means 'adult human'
- wo-man is adult female (somtimes wif-man)
- were-man is adult male: not often used, now seen mostly in were-wolf (man-wolf) and in Scots 'fir' or 'fier'* (and Gaidhlg fear / fir) and 'vir' in a number of languages. You can also have wępenmann (weapon-man) meaning male (and an innuenedo on weapon)
And thus 'man-size' = 'adult-human-sized' and manhole, chairman and so on are perfectly descriptive and not in the least sexist.
However, I am old, and usage changes... I have a horse in this race, though, as due to my surname, I am in danger of becoming Mr Personperson.
* Burns', Auld Lang Syne, 'And there's a hand, my trusty fiere!'