In the context of tennis, "stan" refers to an avid, dedicated, or enthusiastic fan of a particular athlete, team, or celebrity. The term originated from the song "Stan" by Eminem, which portrayed an obsessive and overly devoted fan. It has since been adopted as a slang term to describe passionate fans in popular culture. In relation to tennis, a "Wawrinka stan" would be an enthusiastic supporter or fan of the professional tennis player Stan Wawrinka.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Tennis star Wawrinka. Explanations are generated by AI and may be inaccurate.