psycho

psycho — noun

1. an offensive, informal way to refer to someone you believe is crazy, frightening

1.nounB2
Definition

an offensive, informal way to refer to someone you believe is crazy, frightening, or dangerous in the way they act or think — often used as an insult to put someone down.

Example

Trang called her ex-boyfriend a psycho after he smashed her car window.

often used as an insult after threatening behaviour

A security guard warned us the man was a psycho with a violent past.

labelling someone as dangerous or violent

Common collocations
  • a psycho
  • call someone a psycho
  • total psycho
  • like a psycho
Synonyms
  • lunatic

    also very offensive; old-fashioned term for someone mentally ill

  • maniac

    similar force; often suggests wild, uncontrolled behaviour

  • nutcase

    informal, offensive; milder than psycho but still insulting

  • psychopath

    more clinical but still offensive when used as an insult for anyone unpleasant

Grammar Patterns

psycho (countable noun)

call + someone + a psycho

be + a psycho

Usage Note

This word is highly offensive and often used as a slur against people with mental health conditions. Avoid using it. In formal writing, use terms like 'person with a mental illness' or 'someone experiencing psychosis' instead.

Common Mistakes

My boss is such a psycho because he works on weekends.
My boss works on weekends.
overusing 'psycho' for ordinary behaviour trivialises mental health issues and is offensive.

psycho — adjective

psycho — prefix

Word family

Synonym discussion

Sense: noun/1

All five words can refer to someone perceived as dangerously crazy, but they differ in tone, origin, and severity. 'Psycho' is the most common slang insult, shortened from 'psychopath' in the 1930s, and carries a dismissive, contemptuous tone. 'Lunatic' is an old-fashioned term rooted in the medieval belief that mental illness was tied to the moon (luna); it is now offensive and sounds dated. 'Maniac' suggests wild, frenzied behaviour — a 'road rager' might be called a maniac — and is often used hyperbolically for anyone acting recklessly. 'Nutcase' is more informal and often jocular, but still degrading. 'Psychopath' has a clinical origin but is widely used as an insult for anyone lacking empathy; it carries more weight than 'psycho' because it references a specific personality disorder. As a rule, none of these words should be used to describe someone with a medical diagnosis. A less offensive option would be to name the behaviour directly: 'He acted violently' is clearer and kinder than 'He's a psycho.'

psycho ↗lunatic ↗maniacnutcasepsychopath

Common collocations

Nouns

Adverbs

  • totally psycho
  • completely psycho

Phrases

  • go psycho
  • like a psycho

Etymology

GreekEnglish

The prefix 'psycho-' comes from the Greek word 'psyche' (ψυχή), which originally meant 'breath' or 'life' and later came to mean 'soul' or 'mind'. In the 1800s, European scientists began using 'psycho-' to form technical terms about the mind — 'psychology', 'psychiatry', 'psychoanalysis'. The standalone slang word 'psycho' emerged in American English around the 1930s as a short form of 'psychopath', and quickly became a casual insult for someone thought to be crazy or dangerous.