out of the question; preposterous; absurd
Strongly dismissive expression used to reject something as completely unreasonable or unthinkable. Often used in formal or emphatic contexts.
Such a demand is out of the question.
I have to say his proposal is preposterous.
沙汰 originally referred to official communication or judgment, and 限り means 'limit' or 'extreme'. The phrase literally means 'the limit of what can be discussed or judged', implying something so unreasonable it cannot even be considered.