Pronunciation: (un-nach'ur-ul, -nach'rul), [key]
1. contrary to the laws or course of nature.
2. at variance with the character or nature of a person, animal, or plant.
3. at variance with what is normal or to be expected: the unnatural atmosphere of the place.
4. lacking human qualities or sympathies; monstrous; inhuman: an obsessive and unnatural hatred.
5. not genuine or spontaneous; artificial or contrived: a stiff, unnatural manner.
6. Obs.lacking a valid or natural claim; illegitimate.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.