A person, sometimes unfortunately either a narcissist or someone who really needs to see a doctor themselves but lacks the executive functioning to work out that they have a problem which is not in the best interests of their patient.
In all cases, if you are going to approach a doctor or any professional with Internet or external information, you had better be sure it's worthy or entertainable
They are typically human in design, about 1.60- 2m in height, usually with 2 legs and the ability to raise or lower your blood pressure through their sheer confidence and aura of rationality.
In a percentages of cases, a doctor is a person who uses their brain and their amazing knowledge banks to treat a person successfully without trying to keep them hanging on like a gravy train drip. These people will try and study your history instead of turning their virtual roulette wheel loaded with 36 drugs.
These people should have the title Dr. DemiGod + <earth name>
"Doctor I don't think you are listening to me"
DOCTOR: "And youuuuuu are? Oh, take some pills and come back on your next pay day."