What does the word un mean?

The word "un" is a prefix that means "not" or "the opposite of". It is used to create antonyms of words, meaning words with the opposite meaning.

Here are some examples:

* Unhappy: Not happy

* Unbreakable: Not breakable

* Unbelievable: Not believable

* Uncertain: Not certain

* Unfair: Not fair

The prefix "un" is a very common one in the English language, and it can be used with a wide variety of words.