Frant Share definition Flag An aunt who is also a good friend to a niece or nephew; most likely close in age to her niece or nephew. Someone who is more like a peer than an aunt. Friend: "Your aunt is only 20?"Niece: "Yeah she's my frant."Friend: "Dude your aunt is so cool."Nephew: "Yeah she's a frant." Frant by poems July 23, 2012 Get the Frant mug.