They run out of clothes (9)
I believe the answer is:
streakers
'they' is the definition.
Both the answer and definition are plural nouns.
Perhaps there's a link between them I don't understand?
'run out of clothes' is the wordplay.
'run' becomes 'streak' (synonyms).
'out of clothes' becomes 'ers' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'streak'+'ers'='STREAKERS'
Can you help me to learn more?
(Another definition for streakers that I've seen is " They run naughtily nude".)