Definition:
"Def" is a slang word that means "definitely" or "for sure."
Use case:
You can use "def" in casual conversations with your friends or acquaintances to express your agreement or certainty about something. For example, if your friend asks if you want to go to the movies tonight, you can say "def" to indicate that you are definitely interested.
• I def need to start exercising more, my clothes are getting tight.
• I def don't want to go to that party, it's always a hot mess.
• She def knows how to throw a good party, I had a blast last weekend.
• That movie was def boring, I almost fell asleep.
• That new album is def fire, I've been bumping it non-stop.
• I'm def gonna need some coffee to get through this workday.