Telling poor Clare to hold it (7)
I believe the answer is:
recital
'telling' is the definition.
(thesaurus)
'poor clare to hold it' is the wordplay.
'poor' indicates an anagram.
'to hold' means one lot of letters goes inside another.
'clare' with letters rearranged gives 'recal'.
'recal' placed around 'it' is 'RECITAL'.
(Other definitions for recital that I've seen before include "Solo music performance" , "Concert by soloist" , "gig" , "Concert performance" , "Article found in performance" .)