Refuse to admit what's concealed by the downtrodden youths (4)
I believe the answer is:
Here is my best explanation:
'refuse to admit' is the definition.
'what's concealed by the downtrodden youths' is the subsidiary indication.
'what's concealed' says the answer is hidden in the clue.
'deny' is hidden in the letters of 'by downtrodden youths'.
(Other definitions for deny that I've seen before include "Refuse to give", "Refuse; repudiate", "Refuse to admit the truth", "Reject as false", "Abnegate", "Declare untrue", "Refuse to accept", "Gainsay", "Refuse to admit (something)" and "contest".)