A tall and/or exceedingly slender woman with no hips, a flat buttocks and large, protruding breasts. Grapefruit may be substituted for any fruit that grows on a tree but which more closely approximates the size of the breasts at hand (pun intended).
Man 1: What do you think of Angelina Jolie?
Man 2: Well, her lips make her look like she's trying to swallow a pair of boxing gloves and the rest just looks like someone trained a grapefruit tree to walk.
Man 1: Harsh.
Man 2: That's how I roll.