Odd bits of brass in bowl (5)
I believe the answer is:
'bowl' is the definition.
'odd bits of brass in' is the wordplay.
'odd bits of' means one should take alternating letters.
The alternating letters of 'brass' are 'bas'.
(Other definitions for basin that I've seen before include "Land drained by a river" , "container" , "Sink for washing" , "Stoup" , "Large bowl" .)