精密
せいみつ · seimitsu · JLPT N1 · na-adj
precise
精 — rice 米 + blue/green 青 (phonetic)
A semantic-phonetic compound: 米 (rice) gives the meaning, while 青 supplies the sound. Originally referred to polished, refined rice — grain with the husk removed. The sense broadened to 'refined, pure, essence,' and later 'fine, skilled, spirit.'
密 — 宀 roof + 必 (phonetic) + 山 mountain
Originally referring to a hidden, sheltered place in the mountains, 密 combines 宀 (roof/cover) over 必 (phonetic) with 山 (mountain) at the base. The meaning extended from 'secluded mountain hideaway' to 'dense, close, secret'. Today it commonly means dense, intimate, or secret.