Doctor takes no time in saying a little (7)
I believe the answer is:
modicum
'a little' is the definition.
(thesaurus)
'doctor takes no time in saying' is the wordplay.
I cannot quite understand how this works, but
'doctor' could be 'mo' (medical officer) and 'mo' is located in the answer.
This explanation may well be incorrect...
(Other definitions for modicum that I've seen before include "I cod Mum into providing a small quantity" , "Tad" , "dash" , "suggestion" , "A small portion" .)