A jumping finish is plentiful (9)
I believe the answer is:
abounding
'plentiful' is the definition.
(I've seen this before)
'a jumping' is the wordplay.
'jumping' becomes 'bounding' ('bound' can be a synonym of 'jump').
'a'+'bounding'='ABOUNDING'
'finish is' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for abounding that I've seen before include "in huge numbers?" , "Plentiful" , "filled up" , "Rich" , "Existing in large numbers" .)