What does abnormal mean?
"Abnormal" is an adjective describing something that deviates from what is normal, usual, or expected. It can apply to physical phenomena, such as abnormal weather patterns or abnormal test results, as well as to human behavior or psychological states, where it often takes on a more clinical or diagnostic meaning. Because it implies a departure from a standard, the word can carry negative or judgmental connotations, particularly when used about people; in careful or sensitive writing, alternatives like "atypical" or "unusual" may soften this tone. In medicine, psychology, and statistics, however, "abnormal" serves as a precise, neutral technical term identifying results or conditions outside established ranges of health or typical variation. Derived forms include the adverb "abnormally" and the noun "abnormality." The word traces back through Latin to the Greek "anomalos," meaning uneven or irregular, sharing its origin with "anomaly." Its usefulness lies in flagging deviation clearly and efficiently across scientific, medical, and everyday contexts alike.
adjectiveDeviating from what is normal, usual, or expected; not typical or average.
- Deviating from what is standard, average, or expected; not normal in a statistical or general sense
- (Medicine/Psychology) Indicating a condition, symptom, or behavior that departs from healthy or typical functioning
"The blood test revealed abnormally high levels of glucose in his bloodstream."
"The patient showed abnormal brain activity during the sleep study."
"It was abnormal for her to arrive late, so her colleagues immediately sensed something was wrong."
"Abnormal" comes from the Greek word for uneven or irregular — the same root that gave us "anomaly," literally meaning "not even."
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of abnormal
"Abnormal" entered English in the early 19th century, formed by combining the prefix "ab-" (from Latin, meaning away from) with "normal." The underlying root traces to the Greek "anomalos," meaning uneven or irregular, which passed into Latin as "anomalus" before influencing English vocabulary. Cognates sharing this Greek heritage include "anomaly" and "anomalous," both describing deviations from the expected.
Related word forms
How abnormal is actually used
"Abnormal" carries a clinical or evaluative connotation and can sound judgmental when applied to people or their behavior; in sensitive contexts, terms like "atypical" or "unusual" are often preferred. In medicine and psychology it has a precise technical sense referring to deviation from established norms of health or functioning. The adverb "abnormally" frequently intensifies adjectives (e.g., "abnormally cold").
Easily confused with abnormal
"Abnormal" means deviating from the norm in any direction, while "subnormal" specifically means below the normal level or standard.