1. (法律意义上的)成年人
An adult is a mature, fully developed person. An adult has reached the age when they are legally responsible for their actions.
e.g. Becoming a father signified that he was now an adult...
当了父亲意味着他已是个成年人了。
e.g. Children under 14 must be accompanied by an adult.
14岁以下的儿童必须由成人陪同。
2. 成年动物
An adult is a fully developed animal.
e.g. ...a pair of adult birds.
一对成年鸟
3. 成年的;属于成人的
Adult means relating to the time when you are an adult, or typical of adult people.
adult
e.g. I've lived most of my adult life in London.
我成年之后的大部分时间都是在伦敦度过的。
4. 成熟的;老成的
If you say that someone is adult about something, you think that they act in a mature, intelligent way, especially when faced with a difficult situation.
e.g. We were very adult about it. We discussed it rationally over a drink.
在这件事上我们表现得很成熟。我们一边喝酒一边心平气和地谈了谈。
e.g. ...dealing with emerging sexuality in an adult way.
平静对待出现的性征
5. (涉及性内容的电影或书籍)仅限于成人的
You can describe things such as films or books as adult when they deal with sex in a very clear and open way.
e.g. ...an adult movie.
成人电影