异性

the opposite sex / of the opposite sex / heterosexual / different in nature

different / other / hetero- / unusual / strange / surprising / to distinguish / to separate / to discriminate

nature / character / property / quality / attribute / sexuality / sex / gender / suffix forming adjective from verb / suffix forming noun from adjective, corresponding to -ness or -ity / essence / CL:個|个[ge4]

opposite polarities attract / (fig.) opposite sexes attract / opposites attract

difference

heterosexuality / heterosexual love

heterosexism

heterosexual sex

specific / specificity / idiosyncrasy