Child tracks men on foot (8)
I believe the answer is:
infantry
'men on foot' is the definition.
'infantry' can be an answer for 'foot' (I've seen this before). I am not certain of the 'men on' bit.
'child tracks' is the wordplay.
'child' becomes 'infant' (infant is a kind of child).
'tracks' becomes 'ry'.
'infant'+'ry'='INFANTRY'
Can you help me to learn more?
(Other definitions for infantry that I've seen before include "Unmounted fighters" , "Grunts" , "Foot-soldiers" , "Men fighting" , "part of the army" .)