刻

Phono-semantic compound:

刀 (칼 도, “knife”) — semantic, representing cutting or carving.

亥 (돼지 해, “12th earthly branch”) — phonetic, providing the sound gak.

The original form depicted the action of cutting with a knife, hence “to carve.” The extension to “severe, harsh” comes from the idea of cutting sharply.

Semantic development: from the physical act of engraving → to severity/harshness (as if “cut sharply”) → to a unit of time, a “carved division” of the day.

각인 (刻印) — engraving, imprint

각서 (刻書) — a written pledge, memorandum

시각 (時刻) — time, moment

각별 (刻別) — particularly, especially

각박 (刻薄) — harsh, severe