A good score, I see, can be stimulating (5)
I believe the answer is:
tonic
'be stimulating' is the definition.
(thesaurus)
'a good score i see' is the wordplay.
'a good score' becomes 'ton' (I can't explain this - if you can you should believe this answer much more).
'see' becomes 'C' (the word for the letter, according to Chambers).
'ton'+'i'+'c'='TONIC'
'can' is the link.
Can you help me to learn more?
(Other definitions for tonic that I've seen before include "Carbonated mixer" , "An enlivener" , "requirement for invigoration?" , "Invigorating medicine - keynote" , "It goes with gin" .)