lose one's marbles

idiom

Definition of lose one's marbles

informal + humorous
: to become insane When he started ranting about how the government was out to get him, I thought he'd lost his marbles.

Learn More about lose one's marbles

Share lose one's marbles

Statistics for lose one's marbles

Look-up Popularity

Comments on lose one's marbles

What made you want to look up lose one's marbles? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

to reflect, repel, echo, or resound

Get Word of the Day daily email!

Test Your Vocabulary

Original Meanings Quiz

  • rembrandt-painting-a-young-scholar-and-his-tutor
  • Which of the following is the earliest known sense of the word awe?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

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