A gent in court made little headway with the movement (5)
I believe the answer is:
crept
'little headway with the movement' is the definition.
I can't judge whether this definition defines the answer.
'a gent in court' is the wordplay.
'a gent' becomes 'rep' (I am not sure about this - if you are sure you should believe this answer much more).
'in' means one lot of letters goes inside another.
'court' becomes 'ct'.
'rep' put inside 'ct' is 'CREPT'.
'made' is the link.
Can you help me to learn more?
(Other definitions for crept that I've seen before include "Went stealthily or furtively" , "Moved slowly and carefully" , "Sneaked" , "Moved slowly with stealth and caution" , "Crawled" .)