Back street containing inferior soldiers (6)
I believe the answer is:
troops
'soldiers' is the definition.
(I've seen this before)
'back street containing inferior' is the wordplay.
'back' is a reversal indicator.
'street' becomes 'st'.
'containing' indicates putting letters inside.
'inferior' becomes 'poor' (similar in meaning).
'st' placed around 'poor' is 'spoort'.
'spoort' reversed gives 'TROOPS'.
(Other definitions for troops that I've seen before include "Soldiers, armed forces" , "Cavalry" , "Army" , "Military divisions" , "Groups of soldiers" .)