冷酷
れいこく · reikoku · JLPT N1 · na-adj
ruthless
冷 — ice radical 冫 + order 令
A semantic-phonetic compound. The left side 冫 (ice) supplies the meaning of coldness, while 令 (lìng, 'command/order') hints at the pronunciation. Originally referring to the chill of ice, 冷 broadened to mean cold in general, and figuratively cool, indifferent, or detached.
酷 — wine radical 酉 + announce 告 (phonetic)
A semantic-phonetic compound: 酉 (wine jar) gives the meaning side, while 告 supplies the sound. It originally meant 'strong wine' or intensely flavored liquor. The sense extended to 'extreme' or 'cruel,' and in modern Mandarin it also borrows the English word 'cool.'