The Merriam-Webster dictionary is as official as it gets. It says dude can mean several things. First, it can mean a man extremely fastidious in dress and manner. It also means a city dweller unfamiliar with life on the range. Are many people familiar with the range these days? It also simply refers to a guy or a fellow. It was first seen in literature in 1883 making fun of fashion saying “dude” instead of “dud”. It is thought to be of Scottish origin.
The female version of dude is often said to be dudette and often used as so. Again, Merriam-Webster has the real answer, though. The fine dictionary says that the female version of a dude is actually a dudine. Your world is shaken at this point, and I understand why. Don’t worry, though. Dude is used as slang, and dudette is known and used in a slang manner, too. So, rest assured you can still say dudette and no one will get confused. Wow people at sophisticated parties and tell them the female version of dude is actually dudine. It’ll really impress the crowds.