To sweeten something means to make it taste sweeter by adding sugar, honey, syrup, or another sweet ingredient. You might sweeten your oatmeal with brown sugar, sweeten your tea with honey, or sweeten a smoothie with ripe bananas. Bakers sweeten their cakes and cookies with sugar, while some people prefer to sweeten their coffee with artificial sweeteners that have fewer calories.

The word also means to make something more appealing or attractive, like adding something extra to make a deal better. A parent might sweeten the deal by offering ice cream after dinner if you finish your vegetables first. A seller might sweeten an offer by throwing in free delivery. When your older sister agrees to help with your chores but asks for five dollars, and you counter with three dollars plus letting her borrow your new game, you're trying to sweeten your offer.

You might also hear someone say they need to sweeten someone up, which means being extra nice to them, often because you want something. If you're hoping your dad will drive you to your friend's house, you might sweeten him up by offering to wash his car first. Notice how sweetening, whether it's adding sugar to lemonade or extras to an agreement, is all about making something more pleasant or desirable.