Retinue try very hard without leader (5)
I believe the answer is:
train
'retinue' is the definition.
(both can mean people following an important person)
'try very hard without leader' is the wordplay.
'try very hard' becomes 'strain' (to strain is to try hard).
'without leader' means to remove the first letter.
'strain' with its initial letter taken off is 'TRAIN'.
(Other definitions for train that I've seen before include "Work out" , "Coach; attendants" , "Long back section of a gown that's drawn along the floor" , "Locomotive plus carriages" , "Locomotive or part of bride's dress" .)