冷淡
れいたん · reitan · JLPT N1 · na-adj
indifference
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.
淡 — water radical 氵 + 炎 (flame, phonetic)
淡 combines the water radical 氵 with 炎 (flame), which serves mainly as the phonetic component. The original sense relates to water that is thin or weak in flavor — diluted. From this it extended to mean bland, light, faint, or pale, as in pale colors or weak tea.