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headcase

British  
/ ˈhɛdˌkeɪs /

noun

  1. informal an insane person

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Nathan: If you asked my mam or dad, they'd say I was a headcase!

From BBC • Mar. 14, 2026

Back in 2000, that film gave Sir Ben Kingsley a perception-altering role as a psychotic headcase.

From BBC • Sep. 12, 2013

I ask him if there was ever a fear he'd be typecast as a Glasgow headcase.

From The Guardian • Aug. 26, 2010

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.