noun, noun which may take the genitive case particle 'no'
Describes something that exists or occurs without human intervention, or a quality that is inherent and unforced. Often used as a no-adjective.
この公園は天然自然のままの景色が残っている。
This park retains scenery that is completely natural.
彼の笑顔には天然自然の優しさがある。
His smile has an innate gentleness.
noun, adverb
naturally; spontaneously; of its own accord
Used adverbially to describe something happening without external force or artificial effort, often with に or as an adverbial noun.
問題は天然自然に解決した。
The problem resolved itself naturally.
子供たちは天然自然
Children learn language spontaneously.
天然 means 'natural' as opposed to artificial, often used for natural resources or innate qualities. 天然自然 doubles the idea for emphasis and is more formal.
A yojijukugo combining 天然 (natural, innate) and 自然 (nature, spontaneous), reinforcing the idea of something being completely natural and unforced.