A sweep, perhaps (3)
I believe the answer is:
oar
'a sweep perhaps' is the definition.
(I know that sweep is a type of oar)
'a sweep' is the wordplay.
I cannot really understand how this works, but
'a' is present in the answer.
The remaining letters 'or' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for oar that I've seen before include "It ends in blade" , "Rowing blade" , "Scull" , "Rower's flat blade" , "Rowing boat operator" .)