a. Not in accordance with what usually occurs in nature: a tree with an unnatural shape.
b. Not included in nature; artificial: hair that had been dyed an unnatural color.
a. Deviating from a behavioral or social norm: a child's unnatural attachment to a doll.
b. Brutal or unfeeling: unnatural cruelty.
3. Stilted, affected, or awkward: an unnatural smile.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.