Mystery-writing award (5)
I believe the answer is:
edgar
'mystery-writing award' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for edgar that I've seen before include "Part of 1 25 [KING LEAR]" , "- Allan Poe, US writer" , "Great writer of spooky stories, . . . . . Allan Poe" , "Chap" , "character in King Lear" .)