turn off 比較常見的意思是「關掉，截斷（電流、煤氣、水等）」，例如：
Please turn the television off before you go to bed.
睡覺前請關上電視。
I forgot to turn off my laptop, and now the battery is dead.
我忘了關掉筆記本電腦，現在電池沒電了。
Please turn the water off when you're done brushing your teeth.
刷牙後請把水關掉。
turn off 還可以意為「拐彎，轉入另一條路」，不能用於被動語態，例如：
Turn off the motorway at the next exit.
在下一個出口拐彎出高速公路。
We turned off the track and headed across the fields.
我們離開跑道，穿過田野。
You need to turn off left just before you get to the village.
在你到村子之前，你得向左轉。
We turned off the main road.
我們拐彎離開了大路。
Turn off when you get to the church.
到了教堂就拐彎。
turn off 還有一個比較不正式的意思，意為「不再聽，不再想」，例如：
I couldn't understand the lecture so I just turned off.
我聽不懂講課，所以也就不聽了。
根據以上的分析，那麼 turn sb off 是關閉某人的某個部位嗎，其實不是，turn sb off 的意思是「使厭煩，使失去興趣」，例如：
People had been turned off by both candidates in the election.
大選中的兩位候選人都讓人覺得掃興。
I thought the subject would be interesting, but the professor's boring lectures really turned me off.
我原以為這門課會很有趣，但教授枯燥的講座真讓我厭煩。
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願意在公路上開車。
turn sb off 還有一個跟兩性有關的意思，意為「使（異性）失去興趣」，例如：
Nothing turns me off like someone who is arrogant.
沒有什麼比一個傲慢的人更讓我失去興趣了。
I think he was turned off by her many tattoos.
我想他因為她身上的紋身對她失去了興趣。
I would think the smell of her breath would turn anyone off.
我想她的氣息會讓任何人對她失去興趣。