Playwright Simon (4)
I believe the answer is:
'playwright simon' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for neil that I've seen before include "- Armstrong, first man to set foot on the Moon" , "- Armstrong, first man to walk on the moon" , "- Simon, US dramatist (Barefoot in the Park)" , "Boy" , "1969 moon walker" .)