In Esperanto you simply add the feminine ending to any noun-there's no exception to any rule.
"Border, Breed Nor Birth"
Dallas McCord Reynolds
Our two toboggan men were possibly vigilant and reassuring beyond the common, but one was quite silently so; the other, who spoke a little English, encouraged us from time to time to believe that they were "strong mans," afterward correcting himself in conformity to the rules of Portuguese grammar, which make the adjective agree in number with the noun, and declaring that they were "strongs mans."
"Roman Holidays and Others"
W. D. Howells
What vexed me a little in one or two of the journals was an attempt made to fix me in a school, and the calling me a follower of Tennyson for my habit of using compound words, noun-substantives, which I used to do before I knew a page of Tennyson, and adopted from a study of our old English writers, and Greeks and even Germans.
"The Letters of Elizabeth Barrett Browning (1 of 2)"
Frederic G. Kenyon