"Lesnar" definitely sounds German, though, or at least Germanic.
"Definitely" is only if you don't know where Slovenia is and what their language and names sounds. I put my bet on him being Slovenian, with that specific suffix at the end ("nar", used as a sign of proffesion of a person, imitating or orginating from german "ner")& Slavic, notably Slovenian, word for wood or forest - "les" (as a member Baby Jay D already said). Etimology woud be "someone who deals with wood", either lumberjack, wood dealer or even a carpenter.
I know many Slovenians (it's harder to trace them elsewhere, small nation), and lot of them has similar sounding surnames.
And yes, many of them are blond, being both german influenced and Slavic.