nope
An informal, casual way to say no.
Nope is an informal way to say “no.” It's casual and often a bit emphatic, like you're making your answer extra clear. When your friend asks if you want to trade lunches and you say nope, you're not being rude, you're just being direct and relaxed about it.
The word has a certain finality to it. If someone asks “Are you going to eat that last cookie?” and you reply nope, you're shutting down the question quickly and completely. It's punchier than a simple “no” but friendlier than “absolutely not.”
You'll hear nope in casual conversation, but you probably wouldn't use it with a teacher asking if you finished your homework, or in other situations where you need to sound more formal or respectful. It's the kind of word that works great with friends and family but might seem too casual for a job interview or a formal letter.
Some people stretch it out for effect: “Nooope, not doing that!” The word itself almost sounds like what it means: a quick closing of possibilities, like a door clicking shut.