Pass out, seeing snakes (4)
I believe the answer is:
asps
'snakes' is the definition.
(asp is a kind of snake)
'pass out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'pass' with letters rearranged gives 'ASPS'.
'seeing' is the link.
(Other definitions for asps that I've seen before include "Pass among snakes" , "Poisonous snakes" , "Poplars" , "Small vipers" , "Cleopatra's cobras" .)