I would definitely say it is the person who gets drunk everyday. It is an illness that these individuals can't overcome. They need to drink everyday and it isn't just one or two. These people get motherlessly drunk daily.
I drink once in a blue moon and I am not reliant on drink at all. I would think it would be horrific being an alcoholic and having no control. It is a disease that people try and hide but eventually it comes out as the person deteriorates and increase the drinking episodes.
One of my old bosses became an alcoholic and hid it from everyone for over a year. He had treatment but relapsed soon afterwards.
In my opinion an alcoholic is a person who cannot skip one or two days drinking. Often those people are not even aware that they are addicted to alcohol. The very occasional drink however should be no problem, although without getting drunk. One should know when to stop and ideally that would be before getting intoxicated.
A person who gets drunk from time to time and thus the occasional binge drinker has in my opinion a problem too. I would refer to them as occasional alcoholic. Although they might not drink often they still seem not to know when to stop or they do not see any necessity to stop or they simply can‘t.
My own understanding of someone who is an alcoholic is someone who is an alcohol addict. Meaning that someone who drinks everyday is an alcoholic.
Another meaning of an alcoholic is someone who get drunks of alcohol all the time therefore someone who gets drunk from time to time is not an alcoholic as he is someone that does not abuse alcohol all the time.
So someone who gets drunk from time to time can not be referred to as an alcoholic. But someone who gets drunk everyday and someone who abuses alcohol can be called an alcoholic.