A whit is a tiny amount of something, so small it's barely worth mentioning. When someone says “I don't care one whit about that,” they mean they don't care even the tiniest bit. If a strict teacher doesn't ease up one whit on homework over the holidays, she's not reducing it even slightly.

The word often appears in phrases like “not a whit” or “every whit,” emphasizing how complete something is. If you're not a whit sorry for standing up to a bully, you have absolutely no regret. If your project is every whit as good as your classmate's, it's completely equal in quality.

Think of a whit as smaller than a speck, tinier than a smidge. It's the kind of word you use when you want to stress that something hasn't changed or moved even the smallest possible amount. You might say your brother hasn't improved his messy room one whit, meaning he hasn't made even the slightest effort to tidy it.