Where an ambitious man puts his foot down (8,5)
I believe the answer is:
stepping stone
'foot down' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'where an ambitious man puts his' is the wordplay.
I cannot quite see how this works, but
'an' could be 'one' and 'one' is present in the answer.
'man' could be 'p' (abbreviation for pawn, a chess piece or 'man') and 'p' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for stepping stone that I've seen before include "means to get better" , "Aid to gradual progress" , "means of advancement" , "Means to gradual progress" , "Part of stream crossing" .)