«فَإِذَا تَعَذَّرَ الْعَمَلُ بِالْحَقِيقَةِ لِمَانِعٍ كَالْعُرْفِ»
Where custom prevents application of the literal sense, the expression may be interpreted according to established usage.
For instance, speech about beating someone “until he dies” can be customary hyperbole for a severe beating, rather than an actual intention to continue striking until death.
The interpreter must identify a real linguistic reason to depart from the literal construction. Custom is not an unrestricted license to disregard an otherwise workable literal meaning.