1: Someone, usually an alcoholic
, who goes around trying to grab unattended and unfinished drinks in a bar or other drinking premises.
2 (literal definition): A moth that has fallen into your beer and drowned.
1: "Damnit Nathan, your stepmom's a beer moth! She drank my drink whilst I was on the crapper
2: "Aw, a moth just drowned in my drink. Better put the lil' guy in the bin."