Not typical, usual, or regular; not normal; deviant.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "abnormal" in a sentence
"He would soon find out that President Eisenhower did not attach the same significance to the word abnormal and had no intention of leaving Berlin."
"AD: Well, I didn't do much of what they call abnormal psych or behavioral psychology but I was studying cognitive science and a lot of cognitive science is things like understanding decisions, theory and probability, statistics and probability, that sort of thing."
"This is true of every marriage, even if no offspring result, just as of every eye it can be said that it is destined and formed to see, even if, in abnormal cases arising from special internal or external conditions, it will never be possible to achieve visual perception."