To faze means to disturb, bother, or throw someone off balance. When something doesn't faze you, it means you stay calm and steady even when things get difficult or surprising.

Imagine a basketball player who keeps making free throws even when the opposing team's fans are yelling and waving signs to distract her. The noise and commotion don't faze her at all. Or think of a student who discovers on test day that the exam covers two extra chapters: if he studied thoroughly and feels confident, the surprise might not faze him.

The word usually appears in negative constructions: “That didn't faze her” or “Nothing fazes him.” When you say something doesn't faze someone, you're noting their composure and resilience. A confident public speaker isn't fazed by tough questions from the audience. An experienced chef isn't fazed when the kitchen gets hot and hectic during the dinner rush.

People sometimes confuse faze with phase, but they're completely different words. Phase refers to a stage or period of time, while faze is about being disturbed or bothered. You go through phases in life, but challenges either faze you or they don't.