unnatural

American  

[uhn-nach-er-uhl, -nach-ruhl] / ʌnˈnætʃ ər əl, -ˈnætʃ rəl /

adjective

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.

   Synonyms:

   aberrant, irregular

4. lacking human qualities or sympathies; monstrous; inhuman.

   an obsessive and unnatural hatred.

   Synonyms:

   brutal, heartless

5. not genuine or spontaneous; artificial or contrived.

   a stiff, unnatural manner.

6. Obsolete. lacking a valid or natural claim; illegitimate.

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unnatural British  

/ -ˈnætʃrəl, ʌnˈnætʃərəl /

adjective

1. contrary to nature; abnormal

2. not in accordance with accepted standards of behaviour or right and wrong

   unnatural love

3. uncanny; supernatural

   unnatural phenomena

4. affected or forced

   an unnatural manner

5. inhuman or monstrous; wicked

   an unnatural crime

6. obsolete illegitimate

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Other Word Forms

• unnaturally adverb
• unnaturalness noun

Etymology

Origin of unnatural

late Middle English word dating back to 1375–1425; un- ¹, natural

Explanation

Something unnatural is strange, fake, or abnormal. If you dye your hair hot pink, it's going to look unnatural — especially to your conservative grandparents. It's unnatural for a wild animal to live inside someone's house; it goes against the way the animal normally lives in its natural environment. You could also describe your bright blue bottle of juice as an unnatural color. And if you try to impress someone by speaking in a French accent, that would also be unnatural. Unnatural adds the "not" prefix un- to natural, which comes from the Latin word naturalis, "by birth," or "according to nature."

Example Sentences

Designed to lower auto emissions by temporarily shutting off the engine while the brake is engaged, it also makes driving feel unnatural, jerky and unenjoyable, Donio and his fellow stop-start haters argue.

From The Wall Street Journal • Apr. 3, 2026

"It felt very unnatural for me, to think: 'Hold on, I need to slow down'."

From BBC • Feb. 21, 2026

Still, it would be hard to object to anyone pursuing initiatives to get unnatural additives out of the food supply or trying to ensure that the country is eating well.

From Salon • Feb. 19, 2026

Across the state, the annual cash payments were not associated with an increase in serious traumatic injuries or deaths from unnatural causes in the short term.

From Science Daily • Feb. 16, 2026

Something about it intensified the green of the lawn so all that vast expanse seemed unnatural, luminous somehow, and not quite of this world.

From "The Secret History" by Donna Tartt

Related Words

• abnormal
• bizarre
• incredible
• odd
• outlandish
• outrageous
• perverse
• preposterous
• stilted
• strange
• unusual