I mean can u become anorexic....from illness..not body image or anything of that sort?

Yes: "anorexia" just means loss of appetite for food. It can be due to many types of physical illnesses, and not from psychological issues at all. The correct term for the psychiatric disorder is "anorexia nervosa", which means anorexia due to a nervous condition.

Anorexic: Yes, you can lose your appetite from illness -- "anorexia" = "loss of appetite." the disorder called "anorexia nervosa" is something different. In plain loss of appetite, people generally want to gain weight back -- but this is not the case w/anorexia nervosa. Also anorexia nervosa does have the body image problem that you mentioned. This is not present with illness-related loss of appetite.