An essential part of the douchebag uniform.* Pair with it what you will - popped collar polo shirts or Dave Matthews Band t-shirts; Smathers & Branson belt or no belt at all; loafers, deck shoes, or flip flops; any baseball cap worn by a person over 17 -- it is the one constant, unifying thread, an unflagging sign of asshattery. Can also be referred to in an homage to a bard whose name is long forgotten as "dick-suck-it reds."
* Note: Like the Jeep Cherokee, it is acceptable for women and adolescents to own nantucket reds; it is only a sign of douchebaggery in adult males. However, even women and children should only wear them after careful consideration.
Hitler: Let's have the Waffen SS wear Nantucket red pants for their uniform! That would look snappy!
Mr Hugo Boss: Mein Fuhrer, while that clearly conveys an asshole vibe, it is hardly intimidating. I recommend sticking with grey, black or olive.
Hitler: Ja, you're right. Can I still use it for the draperies in my bunker?