abnormal
American
adjective
-
not normal; deviating from the usual or typical; extraordinary
-
informal odd in behaviour or appearance; strange
Synonym Usage
See irregular.
Other Word Forms
Etymology
Origin of abnormal
First recorded in 1850–55; ab- + normal; replacing anormal, from Medieval Latin anōrmālus, variant of anōmālus anomalous, influenced by Latin norma norm
Explanation
If you get a snowstorm in the middle of July, you could say that you are experiencing “abnormal weather.” Something that is abnormal is out of the ordinary, or not typical. Abnormal is a combination of the Latin prefix ab which means “away from,” and the English word normal. It essentially means “not normal,” or "unusual.” Abnormal implies that whatever is “not normal” is also undesirable. However, abnormal is sometimes used in a positive context. The phrase “abnormal intelligence,” for instance, usually refers to someone with especially high intelligence.
Vocabulary lists containing abnormal
Lesson 1
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Cormac McCarthy's "The Road"
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"Modern Automotive Technology," Vocabulary from Section 6
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Two of its best-known features are the abnormal accumulation of proteins called amyloid-beta and tau.
From Science Daily ● Nov. 3, 2026
She had routine surgery for craniosynostosis, external, a birth defect affecting the skull, but an abnormal chest X-ray was not flagged.
From BBC ● Oct. 31, 2026
Alzheimer's is the most common type of dementia, while Lewy Body Dementia is another common form caused by abnormal protein deposits, which cause a loss of cognitive function.
From BBC ● Oct. 30, 2026
Tumors carry mutations that can produce abnormal proteins the immune system can recognize.
From The Wall Street Journal ● Oct. 24, 2026
Then new shoots began to be put forth and grew with abnormal rapidity, giving a weeping appearance to the trees.
From "Silent Spring" by Rachel Carson
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
