- Slang. foolish; crazy (used especially in the phrase be illin').
Origin of illin'
First recorded in 1980–85; apparently from ill
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for illin
They have their own language Urban Dictionary helps the non-initiated decipher their “buggin” from their “illin.”11 Ways Rappers Are Just Like Right-Wing Radio Hosts
March 29, 2013