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Etymology
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Noun

 * 1) nature

Adjective

 * 1) natural of nature
 * 2) natural; unstudied
 * 1) natural; unstudied

Adverb

 * 1)  suddenly; all of a sudden; spontaneously
 * 2)  for no good reason
 * 1)  for no good reason

Interjection

 * 1)  what the heck do ya think you're doin'?