1. 不由自主的;不自覺(jué)的 If you make an involuntary movement or exclamation, you make it suddenly and without intending to because you are unable to control yourself.
e.g. Another surge of pain in my ankle caused me to give an involuntary shudder. 腳踝突然又一陣疼痛，痛得我直打哆嗦。
involuntarily His left eyelid twitched involuntarily. 他左眼皮不停地跳。
2. 強迫的;非自愿的 You use involuntary to describe an action or situation which is forced on someone.
e.g. ...insurance policies that cover involuntary unemployment... 涵蓋非自愿失業(yè)的保險單 e.g. Involuntary repatriation of Haitians began this week. 這周已開(kāi)始將海地人強制遣送回國。