abnormal

abnormal — adjective

1. not the same as what most people, animals, or things are like — often a sign tha

1.adjectiveC1
Definition

not the same as what most people, animals, or things are like — often a sign that something is wrong, unhealthy, or harmful, such as an unusually high heart rate or strange behaviour after an accident.

Example

Dr. Aiko said Mia's blood test results were abnormal and asked for a second sample.

predicative use after linking verb 'be'

After the storm, Uri noticed an abnormal smell coming from the kitchen drain.

attributive: abnormal + noun (smell, sound, level)

Common collocations
  • abnormal behaviour
  • abnormal results
  • abnormal heart rate
  • abnormal levels
  • clinically abnormal
Synonyms
  • unusual

    neutral; just means not common, with no worry attached

  • irregular

    stresses a break from a fixed pattern (heartbeat, schedule)

  • atypical

    more formal or technical; common in medicine and science

  • anomalous

    very formal; emphasises that something does not fit a known rule

Antonyms
  • normal

    the direct opposite; what is expected or healthy

  • typical

    matches the usual pattern of a group

Usage Note

Often carries a negative or worrying tone — speakers reach for 'abnormal' when the difference from normal is concerning, especially in medical, scientific, or behavioural contexts. For neutral differences, prefer 'unusual' or 'uncommon'.

Common Mistakes

She has an abnormal hairstyle today.
She has an unusual hairstyle today.
'abnormal' suggests something is wrong; for harmless differences in style or taste use 'unusual'.
The weather is abnormally hot, but everyone is enjoying it.
The weather is unusually hot, and everyone is enjoying it.
if the difference is welcome, 'abnormal' clashes with the positive feeling.

Word family

  • abnormally
    adverbC1
  • abnormality
    nounC1
  • normal
    adjectiveA2
  • normality
    nounC1

Synonym discussion

Sense: adjective/1

All five words point to something that does not match the normal pattern, but they sit at different distances from the speaker's worry. 'Unusual' is the friendliest — it just notes a difference, with no judgement: an unusual name, an unusual hat. 'Abnormal' adds a flicker of concern; doctors, scientists, and worried parents reach for it because the difference may signal that something is wrong. 'Atypical' is its calmer, more clinical cousin, common in research papers and medical reports ('atypical symptoms'). 'Irregular' focuses on a broken pattern over time — an irregular heartbeat, an irregular sleep schedule. 'Anomalous' is the most formal and tends to appear in technical writing about data or readings that defy a known rule. So: an unusual coat (fine), an atypical case (neutral), an irregular pulse (rhythm), an anomalous reading (technical), an abnormal result (worrying).

abnormal ↗unusual ↗atypicalirregular ↗anomalous

Common collocations

Nouns

  • abnormal behaviour
  • abnormal results
  • abnormal levels
  • abnormal growth
  • abnormal heart rate
  • abnormal cells

Adverbs

  • highly abnormal
  • completely abnormal
  • slightly abnormal
  • clinically abnormal

Phrases

  • nothing abnormal
  • something abnormal about
  • considered abnormal

Prepositions

  • abnormal for (a child / the season)
  • abnormal in (size / shape / behaviour)

Etymology

LatinFrenchEnglish

Built from the Latin-rooted 'normal' (from 'norma', a carpenter's square used to check that something is straight or correct) plus the prefix 'ab-', meaning 'away from'. The word entered English in the late 1800s, replacing an older form 'anormal'. So at heart 'abnormal' means 'turned away from the carpenter's square' — bent away from the standard shape.