A 'molinari' is an individual who tries to look like he is muscular and/or has large biceps by wearing small t-shirts. Generally, a molinari will wear small shirts yet still be unable to fill out the sleeves. Molinari's are generally loud attention-seekers.
Dude, check out that molinari wearing the smedium shirt. He better be careful not to spill his peanut butter, jelly, and banana pudding sandwich on it.