half a brain

idiom

Definition of half a brain 

: common sense If he had half a brain, he would have left a long time ago.

Learn More about half a brain

Share half a brain

Statistics for half a brain

Look-up Popularity

Comments on half a brain

What made you want to look up half a brain? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a state of commotion or excitement

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Roman Mythology Quiz

  • the-triumph-of-venus-by-alessandro-magnasco
  • Boreal comes from the name of the ancient Greek god of which wind?
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Word Winder's CrossWinder

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!