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

you'll never know

idiom

: you will never be fully aware (of the extent or degree of something)
You'll never know what this means to me.

Browse Nearby Words

you'll
you'll never know
you're
See all Nearby Words

Cite this Entry

“You'll never know.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/you%27ll%20never%20know. Accessed 1 Dec. 2025.

Copy Citation

Share

Love words? Need even more definitions?

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

Popular in Grammar & Usage

See More

31 Useful Rhetorical Devices

'Affect' vs. 'Effect'

The Difference Between 'i.e.' and 'e.g.'

Why is '-ed' sometimes pronounced at the end of a word?

What’s the difference between ‘cemetery’ and ‘graveyard’?
See More

Popular in Wordplay

See More

Are you in a 'food coma'?

17 Words for Dog Breeds

Words That Turned 100 in 2025

How 'Namaste' Entered The English Language

'Za' and 9 Other Words to Help You Win at SCRABBLE
See More

Popular

See More

31 Useful Rhetorical Devices

Are you in a 'food coma'?

17 Words for Dog Breeds
See More

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