Accepted in error and fainted (6,3)
I believe the answer is:
passed out
'fainted' is the definition.
('pass out' can be a synonym of 'faint')
'accepted in error' is the wordplay.
'accepted' becomes 'passed' (I can't justify this - if you can you should believe this answer much more).
'in error' becomes 'out' (out can mean wrong or inaccurate).
'passed'+'out'='PASSED OUT'
'and' acts as a link.
Can you help me to learn more?
(Another definition for passed out that I've seen is " Graduated - fainted".)