Literally "son or descendant of Levi", thus a Levi (or Levite). The name is Ashkenazic Jewish in origin.
Surprisingly, there was a noble family in Poland named Lewinski (according to Wikipedia). Monica Lewinsky (as far as I know or care to know... well, as far as I know; though now I'm interested in looking up whether Miss Lewinsky) is not related to the Jewish nobles in Poland.
by Nickidewbear August 18, 2011