A frump-a-lump is quite a large, obese chick, one comparable to the size of a cow (rule of thumb), and is quite grotesque in nature. One also possesses behaviours that are quite foul, disgusting and somewhat off putting. You might go as far as saying a frump-a-lump is the perfect mixture between a frumpy and a heffer. Frump-a-lump's can be found across all demographic areas, ranging from lower, middle and upper class. Although most are quite prominent in Low Socio-Economic Status areas such as Dandenong and Croydon.

A casual invitation / threat used by an individual that is not afraid of fucking someone up.

When an old frumpy person humps a tree and They scream so loud China can hear.. or if they're in china, America can hear :)