Non- is a prefix you attach to the beginning of words to mean “not” or “without.” When you add non- to a word, you often create its opposite or show that something lacks a certain quality.

A nonfiction book tells true stories, not made-up ones. Nonviolent protest means demonstrating peacefully, without physical force. A nonsense answer doesn't make sense. Someone with a nonchalant attitude acts calm and unbothered.

Notice how non- differs from un- or in-, which also mean “not.” We say unhappy, not “non-happy,” and incomplete, not “non-complete.” Often, non- creates a neutral opposite (like nonmember, simply someone who isn't a member).

You'll find non- everywhere: nonstop flights that don't land between cities, nonfat milk with the fat removed, nonverbal communication through gestures instead of words. The prefix helps us quickly describe what something isn't without needing an entirely new word. When you understand how non- works, you can figure out hundreds of words you've never seen before.