Revolver in rubbish found by other ranks (5)
I believe the answer is:
rotor
'revolver' is the definition.
(something which revolves)
'rubbish found by other ranks' is the wordplay.
'rubbish' becomes 'rot' (both can mean nonsense).
'found by' says to put letters next to each other.
'other ranks' becomes 'or' (military abbreviation).
'rot'+'or'='ROTOR'
'in' acts as a link.
(Other definitions for rotor that I've seen before include "one lifting chopper?" , "It lifts helicopter" , "Copter blade assembly" , "Arm moving" , "Turning part of an engine" .)