turn off 比较常见的意思是“关掉，截断（电流、煤气、水等）”，例如：
Please turn the television off before you go to bed.
睡觉前请关上电视。
I forgot to turn off my laptop, and now the battery is dead.
我忘了关掉笔记本电脑，现在电池没电了。
Please turn the water off when you're done brushing your teeth.
刷牙后请把水关掉。
turn off 还可以意为“拐弯，转入另一条路”，不能用于被动语态，例如：
Turn off the motorway at the next exit.
在下一个出口拐弯出高速公路。
We turned off the track and headed across the fields.
我们离开跑道，穿过田野。
You need to turn off left just before you get to the village.
在你到村子之前，你得向左转。
We turned off the main road.
我们拐弯离开了大路。
Turn off when you get to the church.
到了教堂就拐弯。
turn off 还有一个比较不正式的意思，意为“不再听，不再想”，例如：
I couldn't understand the lecture so I just turned off.
我听不懂讲课，所以也就不听了。
根据以上的分析，那么 turn sb off 是关闭某人的某个部位吗，其实不是，turn sb off 的意思是“使厌烦，使失去兴趣”，例如：
People had been turned off by both candidates in the election.
大选中的两位候选人都让人觉得扫兴。
I thought the subject would be interesting, but the professor's boring lectures really turned me off.
我原以为这门课会很有趣，但教授枯燥的讲座真让我厌烦。
I know that the accident really turned Janet off to driving on the highway.
我知道那次事故真的使珍妮特不愿意在公路上开车。
turn sb off 还有一个跟两性有关的意思，意为“使（异性）失去兴趣”，例如：
Nothing turns me off like someone who is arrogant.
没有什么比一个傲慢的人更让我失去兴趣了。
I think he was turned off by her many tattoos.
我想他因为她身上的纹身对她失去了兴趣。