Thanks for the input on if it's a glass or a bottle that's half full / half empty. This reminds me that linguistically, we each have what is called an ideolect, our own personal version of the language we speak.
An example of ideolect is for me personally is the following
I don't know whether to go on vacation. 
I don't know whether to go on vacation or not. 
For me personally, the first one is wrong, and the second is the only right way to say it. But there are native English speakers who will disagree with me.
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In regards to the terms drunker, drunkard and drinker.
drunker is the comparative:
I'm drunker than she is.
Estoy más emborrachado que ella.
drunkard = borracho (you can also use drunk)
He's a drunkard.
He's a drunk.
El es borracho.
drinker refers to someone who drinks (usually speaking of alcoholic beverages) This does not imply that the person is a drunk or drunkard.
She's a social drinker.
He's a light drinker.
Alfonso's an optimistic drinker.