1. not injurious to physical or mental health • Ant: noxious • Similar to: innoxious • See Also: harmless 2. not causing disapproval - it was an innocuous remark - confined himself to innocuous generalities - unobjectionable behavior • Syn: unobjectionable • Similar to: inoffensive 3. lacking intent or capacity to injure - an innocent prank • Syn: innocent • Similar to: harmless