Succeeded with fish spear (5)
I believe the answer is:
spike
'spear' is the definition.
(I know this)
'succeeded with fish' is the wordplay.
'succeeded' becomes 's' (genealogical abbreviation).
'with' says to put letters next to each other.
'fish' becomes 'pike' (pike is a kind of fish).
's'+'pike'='SPIKE'
(Other definitions for spike that I've seen before include "Unexpected amount of juice" , "Large nail; thwart" , "comedian of old" , "Decide not to run" , "spear" .)