A combination of Nigger and Raydar. Commonly used by white supremascists, racists, or the Klu Klux Klan as a way to detect near by black people. Nigdar use has been reported in southern regions of the United States. Although it's popularity has died down, there are still secluded incidents of nigdar's throughout the US.
"Klansmen, my nigdar is picking up a large quantity of negroes, gather your rope!"
by Matt Noogertson March 25, 2006