To inflate means to fill something with air or gas so it expands and gets bigger. When you inflate a balloon, you blow air into it until it swells up tight and round. Before a basketball game, players check that the ball is properly inflated so it bounces correctly. Hot air balloons inflate with heated air that lifts them into the sky.

The word also describes making numbers or importance seem bigger than they really are. A student might inflate how much time they spent on homework, claiming three hours when it was really just one. Politicians sometimes inflate their accomplishments to impress voters. Companies might inflate their sales numbers to attract investors. When prices inflate, they rise higher and higher, which is why we call rising prices inflation. If you bought a candy bar for a dollar last year but it costs two dollars this year, that price has inflated.

The opposite of inflate is deflate. A deflated tire needs air. A deflated person feels discouraged, as if the air has been let out of them. When someone deflates your inflated story by pointing out the truth, they're bringing it back down to reality.