the world > life > the body > external parts of body > trunk > back > buttock(s) > [adjective] > types of > person having (3)
Of a person: having large or broad buttocks (used chiefly as a term of abuse). rare (archaic in later use).
Of a person: that has large buttocks (often depreciative). Earliest in extended use: (of a thing) that has a wide base or bottom; = big-assed, adj. 1.
That has large buttocks (cf. ass, n.2 1a).