男女

male-female / male and female

male / Baron, lowest of five orders of nobility 五等爵位[wu3 deng3 jue2 wei4]

female / woman / daughter

archaic variant of 汝[ru3]

men, women, young and old / all kinds of people / people of all ages

equality of the sexes

men, women, young and old / everybody

see 男女同校[nan2 nü3 tong2 xiao4]

coeducation

men and women should not touch hands when they give or receive things (citation, from Mencius)

man-woman connection / intimate relationship

to be promiscuous / to sleep around

wife's sister's children

a couple engaged in an illicit love affair / a cheating couple