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1 definition by Mister Schmidt

 
1.
Someone who is a crackerjack, is someone who is greatly humourous, and is able to "crack" you up, i.e, induce a great amount of laughter from you.
Adam: So then I said, that's not a chevy, it's a fjord!

Gary: You're a real crackerjack, Adam.
by Mister Schmidt May 23, 2010