Naval officer, one found in Botswana, surprisingly (9)
I believe the answer is:
boatswain
'naval officer' is the definition.
(thesaurus)
'one found in botswana surprisingly' is the wordplay.
'one' becomes 'i' (Roman numeral).
'found in' means one lot of letters goes inside another.
'surprisingly' is an anagram indicator (a surprising ordering of the letters).
'botswana' is an anagram of 'boatswan'.
'i' going within 'boatswan' is 'BOATSWAIN'.
(Other definitions for boatswain that I've seen before include "4 [TEMPEST] character" , "Warrant officer in charge of a ship's crew" , "Seaman" , "Crew member" , "I was not AB (anag) - naval warrant officer" .)