sex

noun

• 1 [mass noun] (chiefly with reference to people) sexual activity, including specifically sexual intercourse:he enjoyed talking about sex she didn’t want to have sex with him
• [in singular] euphemistic a person’s genitals.

• 2either of the two main categories (male and female) into which humans and most other living things are divided on the basis of their reproductive functions:adults of both sexes
• [mass noun] the fact of belonging to either the male or female sex:direct discrimination involves treating someone less favourably on the grounds of their sex
• the group of all members of either the male or female sex:she was well known for her efforts to improve the social condition of her sex

verb

• 1determine the sex of: each bird would need to be individually sexed

• 2 (sex something up) informal present something in a more interesting or lively way.

• 3 (sex someone up) informal arouse or attempt to arouse someone sexually.