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' is an anagram of 'ASPS'.
'seeing' acts as a link.
(Other definitions for asps that I've seen before include "Pass among snakes" , "Poisonous snakes" , "Poplars" , "Small vipers" , "Cleopatra's cobras" .)