1 male or female
ADJ. female, male | opposite At that age they can started becoming shy with the opposite sex. | single a single-sex school | fair/fairer, gentle (humorous) (= women; some women may find these terms annoying)
SEX + NOUN change She's had a sex change operation. | equality | discrimination, inequality | ratio
PREP. between the ~es differences/inequalities/relations between the sexes
PHRASES the battle of the sexes The quiz is a battle of the sexes between a team of male students and a team of female students. | on grounds of sex discrimination on grounds of sex | irrespective/regardless of sex The word ‘man’ can refer to all humans, irrespective of sex.
2 sexual intercourse
ADJ. anal, oral, penetrative, vaginal | gay, homosexual, lesbian | heterosexual | good, great, passionate | safe | unprotected, unsafe | consensual, non-consensual | extra-marital, illicit, premarital | kinky | casual, promiscuous | unlawful He was convicted of having unlawful sex with an underage girl. | explicit, gratuitous Films containing explicit sex are banned.
VERB + SEX engage in, have She had never had sex before. | consent to | refuse | obtain, procure
SEX + NOUN life a healthy sex life | drive, urge a low sex drive | appeal Despite his age, he still has a lot of sex appeal. | act, practices photos showing sex acts safer sex practices | therapist, therapy | organ | hormone | education | abuse, assault, attack, crime, offence child sex abuse | maniac He had a reputation of being a sex maniac. | fiend (informal), offender, pest (informal) | film, scene, show | symbol She wants to be known as a singer rather than as a sex symbol. | shop | aid, toy | scandal
PREP. ~ between sex between consenting adults | ~ with sex with her husband