1
general::
Impossible, not worth considering, as in Starting over again is certainly out of the question. This term uses question to refer to what is being talked or asked about. [c. 1700]
American Heritage Idioms
2
general::
Phrase(s): out of the question
Fig. not allowed; not permitted. • I’m sorry, but your taking my car is out of the question. • You can’t go to Florida this spring. We can’t afford it. It’s out of the question.
McGrawhill's American Idioms And Phrasal Verbs