A stimulant is not wrong, I see (5)
I believe the answer is:
tonic
'a stimulant' is the definition.
(I've seen this before)
'not wrong i see' is the wordplay.
'wrong' indicates anagramming the letters.
'see' becomes 'C' (the word for the letter, according to Chambers).
'not' is an anagram of 'ton'.
'ton'+'i'+'c'='TONIC'
'is' acts as a link.
(Other definitions for tonic that I've seen before include "Small drink of spirits" , "Invigorating medicine - keynote" , "It goes with gin" , "Stimulus" , "Quinine water" .)