Reckless during night out, getting corporal punishment (9)
I believe the answer is:
thrashing
'corporal punishment' is the definition.
(thrashing is a kind of corporal punishment)
'reckless during night out' is the wordplay.
'reckless' becomes 'rash' (synonyms).
'during' indicates putting letters inside.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'night' with letters rearranged gives 'thing'.
'rash' put within 'thing' is 'THRASHING'.
'getting' is the link.
(Other definitions for thrashing that I've seen before include "A very heady defeat" , "Hiding" , "punishment" , "beating" .)