Play the silly dupe who became temperamental (5,2)
I believe the answer is:
acted up
'play the silly dupe who became temperamental' is the definition.
The answer and definition are different parts of speech. However, past participle verbs and adjectives occasionally define each other.
'play the silly dupe' is the wordplay.
'play' becomes 'act' (synonyms).
'the silly' indicates an anagram.
'dupe' anagrammed gives 'edup'.
'act'+'edup'='ACTED UP'
Can you help me to learn more?
(Other definitions for acted up that I've seen before include "carried on" , "Behaved badly" .)