One doing the rounds with many clubs? (6)
I believe the answer is:
caddie
'one doing the rounds' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'with many clubs?' is the wordplay.
'with' means one lot of letters goes inside another.
'many' becomes 'D' (Roman numeral for e00).
'clubs?' becomes 'cadie' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'd' going into 'cadie' is 'CADDIE'.
Can you help me to learn more?
(Other definitions for caddie that I've seen before include "Assistant to carry the golf clubs" , "Padraig Harrington's brother-in-law Ronan Flood is also his . . . . . ." , "Golfer's aide" , "assist on course?" , "A golfer's assistant-adviser" .)