Knight on foot is slow man (4)
I believe the answer is:
pawn
'slow man' is the definition.
'pawn' can be an answer for 'man' (man can mean a chess piece). I'm unsure of the 'slow' bit.
'knight on foot' is the wordplay.
'knight' becomes 'n' (chess abbreviation).
'on' says to put letters next to each other.
'foot' becomes 'paw' (paw is a kind of foot).
'n' after 'paw' is 'PAWN'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for pawn that I've seen before include "Hock; cat's-paw" , "Deposit as pledge" , "Lowest ranking chessman" , "Stooge; hock" , "To pop, hock" .)