Mrs Dogberry? (8)
I believe the answer is:
malaprop
'dogberry?' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I don't see?
'mrs' is the wordplay.
I cannot quite see how this works, but
'mrs' could be 'mala' and 'mala' is found within the answer.
The remaining letters 'prop' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for malaprop that I've seen before include "incompetent user of language" , "Mrs -, word-mangling character in The Rivals" , "Mrs ---, Sheridan's word-mangler" , "Female character in The Rivals who uses words wrongly" , "Sheridan's misapplier of words" .)