n hooligan; rabble-rouser. Usually seen in the context of upper-middle-class people referring to the working-classes: Well, yes, Mildred – my Jeremy used to be such a sensible boy but now he’s got mixed up with this awful crowd of yobbos! The derivation of the word is apparently modified back-slang – the moniker “boyo” became “yobbo.” Amusingly, in New York City slang, “yobbos” are breasts. Not in the U.K.