Out of the question
Definition 1 of 1
Pro Tip 1/3Definite Rejection
The phrase communicates a firm 'no'. It's used when there is no chance of changing the decision. 
Asking for a raise right now is out of the question.
Pro Tip 2/3Not An Option
It means that the proposition is not even worth considering. 
Driving in this weather is out of the question.
Pro Tip 3/3Strong Disapproval
It could express strong personal disapproval or advice against a bad idea. 
Cheating on the test is out of the question.