Urban Dictionary Cover-Up
The act of scrambling onto UrbanDictionary.com to quickly find out the definition of a word, usually when used over texts or IM. Used to cover up the fact that you did not know the meaning of the word prior to its use.

Commonly abbreviated to UDCU.
Person A: "yo dude, that jam was live last night."
Person B: *quickly does an urban dictionary cover-up*
"yeah, that was a pretty cool party."