Standard kanji form; 峻 means 'steep, severe' and 酷 means 'cruel, harsh'.
峻刻
Variant using 刻 (carve, severe); less common but attested.
Etymology
Composed of 峻 (steep, severe) and 酷 (cruel, harsh). The exact historical derivation is uncertain; the spelling is conventionally associated with a severe and unfeeling personality.