Let priest go to remove mischievous spirit (11)
I believe the answer is:
poltergeist
'mischievous spirit' is the definition.
(I've seen this before)
'let priest go to remove' is the wordplay.
'to remove' indicates anagramming the letters (move the letters again).
'let'+'priest'+'go'='letpriestgo'
'letpriestgo' is an anagram of 'POLTERGEIST'.
(Other definitions for poltergeist that I've seen before include "Disturbing ghost" , "Troublesome ghost" , "disruptive presence" , "Mischievous spirit" , "Destructive spirit" .)