bumster /ˈbʌmstə/ noun2 •[before a noun] A pair of very low-cut trousers which reveal part of the buttocks.And he would have relished the juxtaposition of the wedding dress with the infamous bumster trousers that are, as of this week, on show in the Metropolitan Museum. — 2011 •In The Gambia, a young man who solicits money or favours from tourists, sometimes in exchange for sex.Believe us when we say, the one thing that is most likely to spoil your holiday in The Gambia is constantly getting hassled by bumsters. — 2006 formsbumsters