Everyone in denial, lately (3)
I believe the answer is:
'everyone' is the definition.
'in denial lately' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ALL' can be found hidden inside 'denial lately'.
(Other definitions for all that I've seen before include "The whole amount" , "without exception" , "that's as many as there are" , "in toto" , "Total" .)