Moose finally died, poor boy (5)
I believe the answer is:
eddie
'boy' is the definition.
(I've seen this before)
'moose finally died poor' is the wordplay.
'finally' indicates one should take the final letters.
'poor' is an anagram indicator.
The last letter of 'moose' is 'e'.
'died' is an anagram of 'ddie'.
'e'+'ddie'='EDDIE'
(Other definitions for eddie that I've seen before include "-- Izzard, comedian" , "-- the Eagle, ski jumper" , "- Cochran, US singer" , "Little Edward" , "Man" .)