天然
てんねん · tennen · JLPT N3 · noun
nature
🌿 天然 = heaven + so-it-is: the way heaven made it, untouched
天 means heaven or sky and 然 means thus or so, so 天然 is how things are by nature, with nothing added by people. 天然水 is natural water. As a slang label, 天然ボケ is someone naturally spacey, airheaded with no act.
天 — 一 (one/sky) above 大 (big person)
Originally a pictograph of a person (大) with an emphasized head, representing what is above — the sky or heavens. The top stroke evolved into 一, symbolizing the vast expanse overhead. From 'sky' it extended to mean 'day,' 'heaven,' and 'nature.'