Mention again about caper (5)
I believe the answer is:
recap
'mention again' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'about caper' is the wordplay.
'about' indicates anagramming the letters.
'caper' is an anagram of 'RECAP'.
Can you help me to learn more?
(Other definitions for recap that I've seen before include "Epitomize" , "Sum up (abbrev.)" , "Go over again with backward pacer" , "Provide summary" , "Summarise briefly (abbr)" .)