Trio ruined performance, getting severe reprimand (4,3)
I believe the answer is:
riot act
'severe reprimand' is the definition.
'riot act' can be an answer for 'reprimand' (riot act is a kind of reprimand). I am not sure about the 'severe' bit.
'trio ruined performance getting' is the wordplay.
'ruined' is an anagram indicator.
'performance' becomes 'act' (act is a kind of performance).
'getting' means one lot of letters go next to another.
'trio' with letters rearranged gives 'riot'.
'riot'+'act'='RIOT ACT'
Can you help me to learn more?
(Other definitions for riot act that I've seen before include "measure to keep order" , "Statute against rowdy behaviour" , "This is read for a severe warning" , "Citator may read this as stern rebuke" , "One read to the unruly once" .)