Users rip off revelation (8)
I believe the answer is:
surprise
'revelation' is the definition.
(thesaurus)
'users rip off' is the wordplay.
'off' indicates anagramming the letters.
'users'+'rip'='usersrip'
'usersrip' anagrammed gives 'SURPRISE'.
(Other definitions for surprise that I've seen before include "Unexpected occurrence" , "Unexpected or astonishing event" , "is not what's expected" , "Shock" , "Bombshell" .)