It was bound to go on foot in Ancient Greece (6)
I believe the answer is:
sandal
'it was bound' is the definition.
The definition suggests a singular noun which matches the answer.
'go on foot in ancient greece' is the wordplay.
I cannot quite understand how this works, but
'go on' could be 'and' (I've seen this in another clue) and 'and' is found in the answer.
The remaining letters 'sal' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for sandal that I've seen before include "Openwork shoe" , "Light open-toed shoe" , "One can go on foot" , "Wood" , "what may be afoot" .)