Naval officer married Lara at sea (4,7)
I believe the answer is:
rear admiral
'naval officer' is the definition.
(thesaurus)
'married lara at sea' is the wordplay.
'at sea' indicates anagramming the letters.
'married'+'lara'='marriedlara'
'marriedlara' with letters rearranged gives 'REAR-ADMIRAL'.
(Other definitions for rear admiral that I've seen before include "navy bigwig" , "Naval officer" , "Top brass" , "Naval rank above commodore" .)