psycho

1 of 2

noun

psy·​cho ˈsī-(ˌ)kō How to pronounce psycho (audio)
plural psychos
informal + disparaging

psycho

2 of 2

adjective

informal + disparaging
: of, relating to, or being a person who is mentally or emotionally unsound or unstable especially in a way that results in dangerous or violent behavior

Examples of psycho in a Sentence

Noun a story based on a real-life psycho who had serious mother-son issues
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Noun
Spoofing slashers and their tired cliches with a new perspective, the comedy features Alan Tudyk and Tyler Labine as good-natured hillbillies assumed to be backwoods psycho killers by a bunch of college students. Brian Truitt, USA Today, 18 Oct. 2025 Driven by Jonny Greenwood’s relentless score, the movie summons not only the images but the psycho-spiritual sensations of a country tearing itself apart. Graham Hillard, The Washington Examiner, 3 Oct. 2025
Adjective
The key figure turns out to be Alex’s mysterious Aunt Gladys, played in full psycho-biddy drag by Amy Madigan. Louis Peitzman, Vulture, 8 Aug. 2025 See All Example Sentences for psycho

Word History

Etymology

Noun

short for psychopath

Adjective

short for psychopathic entry 1

First Known Use

Noun

1919, in the meaning defined above

Adjective

1945, in the meaning defined above

Time Traveler
The first known use of psycho was in 1919

Browse Nearby Words

Cite this Entry

“Psycho.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/psycho. Accessed 25 Oct. 2025.

Kids Definition

psycho

1 of 2 noun
psy·​cho ˈsī-kō How to pronounce psycho (audio)
informal
: a person of unsound mind
used disparagingly

psycho-

2 of 2 combining form
: mind : mental processes and activities
psychotherapy
Etymology

Noun

short for psychopath

Combining form

derived from Greek psychē "soul, mind, principle of life"

More from Merriam-Webster on psycho

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!