bigbottomus Share definition Flag A man or woman with such a large, disproportionate, rotund bottom, that in the animal kingdom they would be considered a 'bigbottomus' "Are we at the zoo or somethin?! Cause that is a bigbottomus!!!" bigbottomus by J.Kelliah August 5, 2017 0 0 Get merch Get the bigbottomus mug. Buy Now — $32.95 See more merch