(slang) The ability to detect whether or not a person is crazy.
2012, Catherine Alvarez-McCurdy, "Halloween Costumes: Least To Most Fuckable", The Chicago Shady Dealer (humor magazine of The University of Chicago), Volume 9, Issue 2, 5 November 2012, page 3:
Someone who likes whips and bondage just as much as you will probably be at the party too; I’m sure your cray-dar will start beeping soon.
2013 October 9, “Zodiac”, in The Valley Beat, number 160, page 26:
Turn on your “cray-dar,” Aquarius. While you love an eccentric individual, this week you could magnetize people who are truly off their rockers.
2015, Sharon Saracino, Smitten with Death[1], The Wild Rose Press, →ISBN:
[…] You put him right in the crosshairs of my mother's cray-dar, and I suspect he'll be keeping a very low profile for a while.”
