Naval officer adapted drama, initially recasting Ariel (4,7)
I believe the answer is:
rear admiral
'naval officer' is the definition.
(I've seen this before)
'adapted drama initially recasting ariel' is the wordplay.
'adapted' is an anagram indicator.
'initially' suggests taking the first letters.
The initial letter of 'recasting' is 'r'.
'drama'+'r'+'ariel'='dramarariel'
'dramarariel' with letters rearranged gives 'REAR-ADMIRAL'.
(Other definitions for rear admiral that I've seen before include "Naval rank above commodore" , "Naval officer" , "Top brass" , "navy bigwig" .)