✨📕 The NEWThe NEW Collegiate Dictionary, 12th Edition Over 5,000 words added — Buy Now! Collegiate Dictionary — Buy Now!

“fly on”

The following 2 entries include the term fly on.

fly on the wall

noun phrase

: someone who is able to secretly watch or listen to other people

See the full definition

fly-on-the-wall

adjective

: having or involving an inconspicuous but effective point of observation

See the full definition

Word of the Day

Listen to the pronunciation of inoculate

See Definitions and Examples »

Test Your Vocabulary

Words Named After People Quiz

  • name tags
  • Namesake of the leotard, Jules Léotard had what profession?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.

Pick the best words!

PLAY
Love words? Need even more definitions?

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

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
petit-fours
Name That Dessert! Hope you’ve saved room for some sweet vocabulary.
See All