Vampire slayer in second opinion? (5)
I believe the answer is:
stake
'vampire slayer' is the definition.
(I've seen this in another clue)
'second opinion?' is the wordplay.
'second' becomes 's' (common abbreviation).
'opinion?' becomes 'take' (I've seen this in another clue).
's'+'take'='STAKE'
'in' acts as a link.
(Other definitions for stake that I've seen before include "Post; money wagered" , "Amount bet" , "Deposit as a wager" , "stout support" , "Post; gamble" .)