Someone who is lazy, frumpy, unmotivated, and apathetic. A Buttertub never questions logic or consequence, and simply indulges on every gluttonous activity that gets in his/her way. Any activity or desire is usually resolved with the quickest, laziest and most unhealthy solution.
The origin of "buttertub" comes from the road "Buttertubs Drive" in Nanaimo, BC, Canada.
Jill "I dunno, shut up, I'm watching my show... Can you carry me to the toilet, I'm too lazy and i gotta take a dump."
John: "God damn, how did I get married to such a buttertub."