adv. from the end : what precedes comes from the speaker's end or ass because of vanity or pride and what follows is more or less the actual truth of the matter.
I thought seriously about going to Harvard buttultimately attended the local junior college.
Our defense played their hearts out and really showed determination buttultimately we couldn't stop the run and they kept scoring.
A burger (or other 'hot' sandwich or snack) purchased from one of those mobile catering outlets gut truck that appears at any outdoors event or outside nightclubs.
A buttism is a statement or expression that just barely misses the mark/point of the conversation and may cause awkward looks or responses from an audience afterwards.