To infuse means to fill something gradually with a quality, flavor, or feeling, letting it spread throughout and become part of the whole. When you make tea, you infuse hot water with flavor by letting the tea leaves steep in it. The leaves release their essence slowly until the entire cup tastes like tea.

The word works beyond the kitchen too. A great teacher might infuse her lessons with humor, weaving jokes and funny stories throughout the material so learning feels lighter and more enjoyable. A composer might infuse a piece of music with sadness by using minor chords and slow tempos that gradually fill listeners with melancholy.

Notice that infusing takes time: it's not dumping something in all at once, but rather letting it spread and permeate. When someone says a speech was infused with passion, they mean that deep feeling showed through in every part of it, coloring the entire message. You might infuse your writing with personality, or a coach might infuse the team with confidence before a big game.