noun. A talent for detecting the Dexters and Hannibals and Denogginizers of the world.
Related terms: dogdar, sexual-geniusdar, someone-is-staring-at-my-ass-dar, weirdo-dar, zombie-dar.
Real citation: "I'm not really enjoying the plot with the potential teen serial killer (especially the Hannibal Lectorish part with the other serial killer knowing by looking at him - do they have serial killer-dar or something?!). But I'm curious to see where it will go."
(Navin, Oct. 1, 2008, "The Shield," Television Without Pity, http://forums.televisionwithoutpity.com/index.php?s=&showtopic=1569855&view=findpost&p=10862840)
Made-up citation: "Serial killer-dar--handy skill for a cop, not so essential in a department-store Santa. Someone had to make that distinction."