not know one's arse from one's elbow

idiom

Definition of not know one's arse from one's elbow 

British, informal + impolite

: to know nothing : to be stupid Don't take his word for it—he doesn't know his arse from his elbow.

Learn More about not know one's arse from one's elbow

Share not know one's arse from one's elbow

Resources for not know one's arse from one's elbow

Statistics for not know one's arse from one's elbow

Look-up Popularity

Comments on not know one's arse from one's elbow

What made you want to look up not know one's arse from one's elbow? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

to reject or criticize sharply

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?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
SCRABBLE® Sprint

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!