A flat, elongated backside, without any shape or definition. Particularly noticeable when wearing jeans (a.k.a. flat butt, frump butt).
Look for panties with posterior padding or shapewear with butt-lifting properties, says Nethero. Glassman suggests jeans with defined rear pockets and strategically placed darting and seams. Finally, wear heels: "They improve posture and lift the butt," he says.
Jeans with small back pockets; high-waist pants.
Jacket, J.Crew. Jeans, Levi's. Earrings, SKU Jewelry, maxandchloe.com. Ring, Lydell NYC. Shoes, Edmundo Castillo, saks.com.