End of puzzle (5)
I believe the answer is:
stump
I believe this is a double definition.
'end' is the first definition.
(thesaurus)
'puzzle' is the second definition.
(I've seen this before)
'of' is the link.
(Other definitions for stump that I've seen before include "Wicket part - dumbfound" , "Confound" , "Remains of felled tree" , "Projecting remnant" , "Wicket upright; greatly puzzle" .)