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1.
1. To crack a huge grin

2. When something makes you so happy that it makes you smile.

3. To make someone else smile

This term originates from the word cheesin, which means having a big smile on your face.
1. I brought something in my bag that's gonna cheese you up!

2. I was so cheesed up when I got accepted to the uni of my dreams

3. Dawg what's wrong with you? You've been frowning all day. Cheese up!
by TheBx41 October 12, 2012