Puzzle remnant (5)
I believe the answer is:
stump
I believe this clue is a double definition.
'puzzle' is the first definition.
(thesaurus)
'remnant' is the second definition.
(thesaurus)
(Other definitions for stump that I've seen before include "clear out of money" , "Remains of felled tree" , "Small remaining part; cricket item" , "Nonplus" , "defeat" .)