If you make an involuntary movement or exclamation, you make it suddenly and without intending to because you are unable to control yourself.
例句
Another surge of pain in my ankle caused me to give an involuntary shudder.脚踝突然又一阵疼痛，痛得我直打哆嗦。
ADJ
强迫的;非自愿的
You use involuntary to describe an action or situation which is forced on someone.
例句
...insurance policies that cover involuntary unemployment...涵盖非自愿失业的保险单Involuntary repatriation of Haitians began this week.这周已开始将海地人强制遣送回国。
英汉词典释义
adv.
不由自主地;本能地
Her eyes strayed involuntarily.她的目光不由自主地移开了。Her hands clenched involuntarily.她本能地攥紧了拳头。She shivered involuntarily as he approached her.他离她越来越近，她不由自主地颤抖起来。