Admiral mortally wounded at Trafalgar (6)
I believe the answer is:
nelson
'admiral mortally wounded at trafalgar' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for nelson that I've seen before include "Victorious flag officer" , "Emma Hamilton's lover, who died in battle on 21 October 1805" , "English admiral, lover of Lady Hamilton" , "Horatio or Mandela?" , "English naval commander - wrestling hold" .)