Snap!
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(oh,) snap
1. An exclamation of shock, surprise, or disbelief when someone says or does something remarkably or controversially incisive, especially an insult or retort. A: "The boss said my work had been getting too sloppy to keep me on the team, so I told her, 'At least my company isn't on the brink of bankruptcy!'" B: "Oh, snap! I can't believe you said that!" A: "I don't know why John is giving you dating advice—he couldn't get a date if he was the last guy on the planet." B: "Hahaha, snap!"
2. An exclamation of dismay or vexation, especially upon remembering or realizing something unfortunate or undesirable. A: "How's studying going for your exam?" B: "Oh, snap! I forgot that was this week—I'd better hit the books!" A: "Remember that I've got work on Saturday, so I need you home to look after your little sister." B: "Snap, that's this Saturday? But I was going to go to Jeff's house for a party!"
3. An exclamation of joy or excitement when something very good or fortunate happens. Just found out I aced my exam—snap! Ohhh, snap—we're going to states!
See also: snap
Snap!
exclam. Wow! Snap! Great idea!