G&S composition is awkward to repeat (8)
I believe the answer is:
operetta
'gs composition' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'awkward to repeat' is the wordplay.
'awkward' indicates an anagram.
'to'+'repeat'='torepeat'
'torepeat' is an anagram of 'OPERETTA'.
'is' is the link.
Can you help me to learn more?
(Other definitions for operetta that I've seen before include "Short amusing opera" , "Make short work" , "Light musical stage work" , "Showboat or The Gondoliers, say" , "work of note" .)