A sex partner with whom one has sex, usually repeatedly, but without any romantic attachment (no strings attached).
Sexual activity, usually sexual intercourse unless preceded by a modifier.
A category into which sexually-reproducing organisms are divided on the basis of their reproductive roles in their species.
Genitalia: a penis or vagina.
Another category, especially of humans and especially based on sexuality or gender roles.
The distinction and relation between these categories, especially in humans; gender.
The members of such a category, taken collectively.
To determine the sex of (an animal).
To have sex with.
To have sex.