Parts of foot missing in second contest with men (5)
I believe the answer is:
chess
'parts of foot' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'missing in second contest with men' is the wordplay.
'missing in second contest' becomes 'cs' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' is an insertion indicator.
'men' becomes 'hes' (I've seen this in another clue).
'cs' going around 'hes' is 'CHESS'.
Can you help me to learn more?
(Other definitions for chess that I've seen before include "In which two bishops will participate" , "Pure-skill board game" , "activity aimed at downfall of a king" , "Sixteen-men-a-side game" , "form of battle" .)