Pronunciation: (un-nach'ur-ul, -nach'rul),[key] —adj. 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.