To have exceptionally flabby upper arms that no amount of pumping iron, doing cardio, and/or starving yourself can alleviate. The most common symptom of the Hilary Duff Arm includes: jiggle without movement, large rosacea-esque markings along the forearms and shoulders, copious amounts of pale skin. See: Kirstie Alley and Pillsbury Dough Boy.
Wow, I tried on my tank top this morning and realized that my Hilary Duff Arms made me look like I had two cheeseburgers attached to my sides.
by A.B."The Pistol"H. October 20, 2005