Big punch up, say, ruined sanctions (5)
I believe the answer is:
okays
'sanctions' is the definition.
(I know this)
'big punch up say ruined' is the wordplay.
'big punch' becomes 'ko' (KO punch is an example. I am not sure about the 'big' bit.).
'up' is a reversal indicator (in down clue: letters go upwards).
'ruined' indicates an anagram.
'ko' reversed gives 'ok'.
'say' anagrammed gives 'ays'.
'ok'+'ays'='OKAYS'
Can you help me to learn more?
(Other definitions for okays that I've seen before include "Sanctions" , "Authorises" , "Gives the go-ahead" , "Agrees" , "Gives the thumbs up" .)