Yuck is what you say when something disgusts you or seems gross. When you bite into food that tastes awful, when you step in something slimy, or when you smell spoiled milk, yuck! perfectly captures that feeling of revulsion.

The word works as both an exclamation and an adjective. You might shout “Yuck!” when your little brother shows you a jar full of dead bugs, or describe overcooked Brussels sprouts as yucky. Some people say ick or ew to mean roughly the same thing, but yuck has a particularly strong, visceral quality that makes it satisfying to say out loud.

Interestingly, what seems yucky varies from person to person and culture to culture. Many American kids think blue cheese tastes yucky, while cheese lovers consider it delicious. Some people think touching worms is yucky, while gardeners handle them without hesitation. Your reaction of yuck tells others about your personal preferences and boundaries, and that's useful information when someone's deciding whether to offer you pickled herring or suggest you pet their tarantula.