sick-ass adjective2 •Mentally disturbed or unsound; malevolently crazy.It's not all right for you to cover for your sick-ass, twisted son, just because he's yours and let him tear apart a woman and her family. — 2007 •Impressive.There's a sick-ass poetry slam every month. Real good stuff. — 2015 formsmore sick ass · more sick-ass · most sick ass · most sick-ass