A man, usually with some form of a undiagnosed mental illness, who knows everything there is to know.
Oh my goodness! Did you hear George telling about how to get rich? He is acting like such a sylvanus.
by jessie_freakgirl February 08, 2009
A sexy ass nigga who likes to mess around with a lot of bitches.
Damn I wish I had a sylvanus
by Mark Royce November 14, 2015