switch off phr v 1 [I,T switch sth ↔ off] to turn off a machine, light etc with a switch 关掉，关上〔机器、灯等〕: Don't forget to switch off the TV when you go to bed. 上床之前别忘了关电视机。 2 [I] informal to stop listening or paying attention 【非正式】 不再听; 不再注意: He just switches off when he's tired. 他累了就走神。