consenting adult
nouna person who is considered old enough, by law, to decide whether they should agree to have sex; a person who has agreed to have sex 到达法定性成熟年龄的已成年人；同意发生性行为的已成年人 What consenting adults do in private is their own business. 到了法定性成熟年龄的成年人私下里做什么是他们自己的事。