put off
Separable
Postpone something
We put off the meeting until Friday.
Make someone not want to do something
The smell of the kitchen put me off my lunch.
Separable
The object can go between the verb and the particle: turn the light off, or turn off the light. When the object is a pronoun it must go in the middle: turn it off, never turn off it.
Practise it
Add it to your daily practice or see every verb with up.
Further reading: put off on Wiktionary (CC BY-SA).