Mistaken, ran out when jeered at (7)
I believe the answer is:
'jeered at' is the definition.
'flouted' can be an answer for 'jeered' ('flout' can be a synonym of 'jeer'). I am not certain of the 'at' bit.
'mistaken ran out' is the wordplay.
'mistaken' becomes 'out' (I can't justify this - if you can you should give a lot more credence to this answer).
'ran' becomes 'fled' (to flee is to run away).
'out' indicates putting letters inside.
'out' placed into 'fled' is 'FLOUTED'.
'when' is the link.
Can you help me to learn more?
(Another definition for flouted that I've seen is " Treated with contemptuous disregard".)