big back Share definition Flag A girl with a big ass / booty. Context: British slang / grime and trap music. Man wants a gyal with a big back. big back by Agrith July 5, 2016 Words you can keep railfan mug chonk mug chud mug based mug 67 mug slime mug mogging mug chopped mug thot mug glazing mug huzz mug yams mug larp mug unc mug cracked mug simp mug baddie mug bop mug lolcow mug