To dissipate means to scatter and gradually disappear, like morning fog that spreads out and vanishes as the sun warms the air. When something dissipates, it breaks apart and fades away until there's nothing left.

Clouds dissipate on a windy day, spreading across the sky until they're gone. Smoke from a campfire dissipates as it rises, getting thinner and thinner until you can't see it anymore. Your anger might dissipate after you cool down and realize the argument wasn't worth getting upset about. A crowd dissipates when people slowly drift away and head home.

The word often describes things that had energy or intensity but lose it over time. A loud noise dissipates as sound waves spread out and weaken. Your nervousness before a presentation might dissipate once you start talking and realize you're doing fine. Heat dissipates from a cup of hot chocolate as it sits on the counter, spreading into the cooler air around it.

Dissipate can also mean to waste something foolishly, especially energy, money, or time. Someone who dissipates their allowance on junk they don't need ends up with empty pockets and nothing to show for it. A student might dissipate their study time by constantly getting distracted. In this sense, the word carries a warning: you're scattering something valuable until it's gone.