A young straight biological male, particularly in his teenage years or early twenties, that bears a striking resemblance to an androgynous lesbian. A heterosexual dude who, at first glance, is often mistaken for a boyish lesbian. He is usually of smaller build, wears ambiguous attire, (ie: skinny jeans, Chuck Taylors) and cuts his hair into a faux hawk or other such lesbian-trademarked coiffure. It might be said of him to have "pretty" features, as well. Due to his tendency to be in touch with his feminine side, he is often pursued by fags, ex-dykes and fruit-flies alike, lending him to get a wider variety of ass than his douchebagy, meathead brethren. However, don't be fooled, my fine lez sisters. The Dubian is indeed a bio-guy, therefore, if you're not into bio-peen, I suggest you stick to dating a bio-boi.
Jenny: What a fine looking butch that 'Bob's Big Boy' is, right? I'm gonna step to her and get me some.
Shane: Oh silly Jenny! I hate to break it to you but that ain't no butch... Big Boy is a Dubian!