Nag about doctor going round for fruit (5)
I believe the answer is:
mango
'for fruit' is the definition.
(type of fruit)
'nag about doctor going round' is the wordplay.
'about' indicates anagramming the letters.
'doctor' becomes 'mo' (medical officer).
'going round' indicates putting letters inside (some letters go around others).
'nag' is an anagram of 'ang'.
'ang' put into 'mo' is 'MANGO'.
(Other definitions for mango that I've seen before include "Fruit, often in chutney" , "Fleshy tropical fruit" , "Asian fruit" , "fruit tree" , "No, Mag has the odd fruit" .)