Char seen when vocalist doesn't finish (5)
I believe the answer is:
singe
'char' is the definition.
(I've seen this before)
'vocalist doesn't finish' is the wordplay.
'vocalist' becomes 'singer' (synonyms).
'doesn't finish' means to remove the last letter.
'singer' with its last letter taken off is 'SINGE'.
'seen when' is the link.
(Other definitions for singe that I've seen before include "Result of burning" , "Sear" , "superficial injury" , "Char, scorch" , "Burn; ignes (anag.)" .)