Blends the words irradiate (to bombard with nuclear radiation) and age. The act of an older staff member skillfully using cutting-edge slang in a formal business setting, such as an office staff meeting, which belies his age and makes his younger rivals appear older and less hip than he. (Radiation therapy in medicine uses beta and gamma rays to destroy young, fast-growing cancer cells in order to preserve the older, healthy tissue.)
My presentation to the big guy was so cool even that snot-nose Jason kept his head down in his Crackberry lookin' shit up. Man, I irradiaged those pups.