out of bounds; beyond the pale
Used for something that is unacceptable, beyond limits, or outside the scope of what is allowed. Often appears in the phrase 埒外に出る or 埒外の.
His behavior is beyond the pale.
That demand is out of bounds.
Compound of 埒 (らち, 'bounds, limits') and 外 (がい, 'outside'). The exact origin of 埒 is uncertain, but it has been used since classical Japanese to mean a fence or boundary, and later figuratively for limits or proper bounds.