Fellows with a lot to put right (4)
I believe the answer is:
mend
'put right' is the definition.
(I've seen this before)
'fellows with a lot' is the wordplay.
'fellows' becomes 'men' (fellow can mean a man).
'with' says to put letters next to each other.
'a lot' becomes 'd'.
'men'+'d'='MEND'
'to' acts as a link.
(Other definitions for mend that I've seen before include "Heal" , "Put right" , "Return to health; repair" , "Fix, repair" , "'Restore, fix (4)'" .)