1.
If you ~ a light or other electrical device, you stop it working by operating a switch.
She switched off the coffee-machine...
Glass parked the car and switched the engine off.
= turn off
PHRASAL VERB: V P n (not pron), V n P
2.
If you ~, you stop paying attention or stop thinking or worrying about something. (INFORMAL)
You may find you’ve got so many things to think about that it’s difficult to ~.
PHRASAL VERB: V P