Unsatisfactory hearing air Holst composed drinking whiskey (4,5)
I believe the answer is:
show trial
'unsatisfactory hearing' is the definition.
The definition suggests a singular noun which matches the answer.
'air holst composed drinking whiskey' is the wordplay.
'composed' indicates an anagram.
'drinking' is an insertion indicator (inserted letters are consumed or drunk).
'whiskey' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'air'+'holst'='airholst'
'airholst' with letters rearranged gives 'shotrial'.
'shotrial' enclosing 'w' is 'SHOW TRIAL'.
Can you help me to learn more?
(Other definitions for show trial that I've seen before include "legal spectacular" , "Travesty of justice" , "Mock public examination" , "Court proceedings where the guilty decision has been decided in advance" , "This process manipulated" .)