A person or thing that for some reason (e.g. for being annoying, a whinger, a loser, or boring, etc.) drains one's energy and general enjoyment of life.
"OMG, I wish Angus would shut up, he's such a drainer."
"Did you go to Stacy's party Saturday night?"
"Yeah, total drainer."
"DRAAAAAAAAAAAINER" (Slow chant to remove offending drainer from giving a speech on some kind of public pedestal)
A drainer is a person who listens/is a big fan of the Swedish music group Drain Gang, wich consists of the members Bladee (CEO), Ecco2K and Thaiboy Digital (or Thaiboy Goon)
A drainer is also very often a alpha male and probably the coolest guy in school
You can also be a fake drain wich is someone who tries to be a drainer without being fully educated in drain, basically a poser
Hello my fellow drainers lets summon a demon together
Look at this fucking poser, he is fake drain
What, are you a drainer???