ADJ
可选择的；非强制的
If something is optional, you can choose whether or not you do it or have it.
例句
A holiday isn't an optional extra. In this stressful, frantic world it's a must...
休假并非可有可无。在这个紧张而忙碌的世界，它是必不可少的。
Sex education is a sensitive area for some parents, and thus it should remain optional.
性教育对某些家长而言是个敏感领域，因此应该保持其非强制性。