no use arguing; not up for discussion
A rare yojijukugo meaning that further debate or discussion is pointless. Often used to cut off argument. Compare the more common 問答無用.
See also: 問答無用
He said 'there's no point in arguing' and cut off the discussion.
問答無用 is the far more common synonym with the same meaning. 問答無益 is a rare variant.
A yojijukugo composed of 問答 (question and answer, debate) and 無益 (useless, futile). The exact origin is uncertain, but it follows the pattern of 問答無用.