The use of an analogy or reference in conversation that is highly academic in nature. Knowledge of the particular reference typically requires advanced study - often in technical fields but is not strictly limited to such. The proper use of a nerd pimpslap will generally cause silence, bewilderment and/or a sense of shocked awe in the audience.
Nerd pimpslapping is the opposite of using analogy to explain complex academic topics. (i.e. using complex analogy to explain simple phenomena)
The reference maker is effectivly slapping his / her audience with academia that is so ostentatious, outlandish, and perhaps pretentious that any further argument is suffocated.
However, care must be taken not to attempt to nerd pimpslap those who are highly educated in the field of reference. Doing so may evoke a response with an even stronger nerd pimpslap.
Special note: pop cultural references to Star Trek, Star Wars and other icons of geekiness do not constitute a nerd pimpslap.
Our teacher asked who was the most important figure in the civil war so Tom gave her a nerd pimpslap, "Abraham Lincoln federated the north and the south like DB2 and Oracle".