River crew with alternating jets (6)
I believe the answer is:
ganges
'river' is the definition.
(I know that Ganges is a river)
'crew with alternating jets' is the wordplay.
'crew' becomes 'gang' (synonyms).
'with alternating jets' becomes 'es' (I can't justify this - if you can you should believe this answer much more).
'gang'+'es'='GANGES'
Can you help me to learn more?
(Other definitions for ganges that I've seen before include "Holy river on India" , "River flowing into the Bay of Bengal" , "Indian flower" , "Sacred Indian river" , "Great river of India" .)