Slender: Thin in an elegant and beautiful way.
Slim: Synonym for "thin" with a positive connotation.
Lanky: Awkwardly tall and thin.
Skinny: Very thin; doesn't eat enough.
Slight Thin as a mirror, can smash into pieces if fallen down.
Petite: Short; often used for women.
Lean & Wiry: Thin and muscular.
Muscular
Well-built: Big and strong.
Ripped: Muscular & in good shape.
Broad: A wide person.
Burly: Strong & heavy like a warrior.
Buff: In great shape.
Beefy: One with a lot of muscles. Often used for men.
Fat
Big-boned: Sugarcoated word for fat.
Chubby: Positive word for fat; "healthy weight".
Matronly: Positive word for a woman who is fat because she has borne children.
Obese: Grossly overweight.
Paunchy: One with a beer belly.
Stout: Fat, thick & short.
Erotic Words for Body
Busty: One with large boobs.
Chiseled: Muscular & well-defined body.
Curvy: Stereotypical female body: thin waist, wider hips, and a proportionate upper body.
Graceful: Sexy, agile, elegant, or well-poised.
Neat: Properly groomed; not thin or fat.
Seductive: Sexually captivating & arousing.
Well-endowed: Used to praise men's genitals.
Other Body Shape Adjectives
Stooped: Having back & shoulders rounded instead of erect.