An ascot is a wide necktie that resembles a small scarf. If you aren't a British earl or Austin Powers, wearing an ascot could be considered a fashion risk.
An ascot is an old-fashioned version of a tie, usually made of narrow silk that gets much wider at the ends and is pinned or tacked at the neck. In the 19th and early 20th centuries, ascots were often worn with morning suits, and today groomsmen in weddings sometimes wear ascots. The word comes from the name of an English village, Ascot, known for meetings requiring formal dress.