Doorman’s endless resilience (6)
I believe the answer is:
bounce
'resilience' is the definition.
(thesaurus)
'doorman's endless' is the wordplay.
'doorman' becomes 'bouncer' (I've seen this before).
'endless' means to remove the last letter.
'bouncer' with its last letter taken away is 'BOUNCE'.
(Other definitions for bounce that I've seen before include "Move energetically; rebound" , "Hop like rubber ball" , "Rebound (of ball)" , "Rebound; self-confidence" , "Throw out" .)