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.
John: "Bitch, that's the 4th Big Mac/Slurpee combo you've had today, and why didn't you go to work?"
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."
A flaccid, shriveled, post-coitus, penis and is still moist and shiny from the amalgam of sexual juices.
After Roger tapped his girlfriend during a lunch time quickie. Sonja went to the bathroom to wash up and grab a doddle rag to come back and wipe off Roger's Butter Thumb.
A short, pudgy person. the term is used to crush that fat fu*k's ego by validly pointing out that she has dehumanized herself by her relentless consumption.
{looking sternly at the BBQ sauce smeared face of your lazy ass wife} "Easy there butterchubbs! Why don't you take it easy on those pulled pork sandwiches! Why don't you get off your huge dumper and get a job!" "Why the fu*k did I knock you up?!#$%"