Assumed monicker made Meldun mope? Twaddle! (3,2,5)
I believe the answer is:
nom de plume
'twaddle' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'assumed monicker made meldun mope?' is the wordplay.
'meldun mope' anagrams to 'NOM DE PLUME'.
But, I'm not clear how this is indicated.
Can you help me to learn more?
(Other definitions for nom de plume that I've seen before include "Pen name" , "Assumed name" , "Soubriquet" , "False name" , "Literary pseudonym" .)