Bad time back in cavalry unit? (5)
I believe the answer is:
troop
'cavalry unit?' is the definition.
(I've seen this in another clue)
'bad time back' is the wordplay.
'bad' becomes 'poor' (similar in meaning).
'time' becomes 't' (abbreviation).
'back' says the letters should be written in reverse.
'poor'+'t'='poort'
'poort' written backwards gives 'TROOP'.
'in' is the link.
(Other definitions for troop that I've seen before include "Flock, large group" , "Squad" , "Military unit" , "Force" , "herd" .)