outside的反义词是inside。outside常见的词性及含义有：adv.在外面；n.外面；adj.外部的；prep.在 ... 外边。例句：

①The outside of it looks all right. 它的外观还可以。

②He isolated himself from the outside world. 他把自己与外部世界隔绝了。inside 常见的词性及含义有：adj.里面的；adv.在里面；n.内部；prep.在 ... 里面。例句：

①He parked his car inside the gate. 他把车停在大门里面。

②We have to play inside because it is raining. 因为天下雨，我们不得不在屋里玩。