Tyson Fury, Nathan Gorman, and Hughie Fury are bums. Proper bums. I'm just kidding... Those bloody bums
B = BELOW U = USABLE M = MEASURE A boxer who's quality isn't measurable, due to lack of sample size or due to excessive losses in that boxer's record. Or, a boxer winning against such an opposition doesn't allow us to gauge how good that boxer is, due to his opponent being a BUM. Typical of vast majority of Deontay Wilder's opponents.
(1) As a noun: Someone who is indigent, homeless. Doesn't have a job. Panhandles for spare change. Lives meal to meal. If he/she is not on the bottom rung of bumhood, does a little couch-surfing at times. as a verb: to 'borrow' something with no plans or intentions of paying it back. (2) a synonym for arse.