snot
Thick, sticky mucus that comes out of your nose.
Snot is the thick, sticky mucus that your nose produces, especially when you have a cold or allergies. When you're sick and your nose is running, that's snot dripping out. When you blow your nose into a tissue, you're getting rid of snot.
Your body makes snot all the time to keep your nose moist and trap dust, germs, and other particles before they can get into your lungs. Usually you don't even notice it. But when you catch a cold or your allergies act up, your nose goes into overdrive and produces way more snot than usual, which is why you end up with a runny or stuffed-up nose.
The word can also describe someone who's bratty or thinks they're better than everyone else: a snotty attitude is one that's mean, superior, and unpleasant. When someone acts snotty, they're being rude in a way that suggests they think you're beneath them, like turning up their nose at your lunch or rolling their eyes at your ideas.