As cads, theyre trodden underfoot (5)
I believe the answer is:
heels
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for heels that I've seen before include "Blackguards in shoes?" , "Parts of shoes" , "Take to them and run away" , "Cobbler does this" , "Foot parts" .)