Investigator cited vet unexpectedly - European (9)
I believe the answer is:
detective
'investigator' is the definition.
(synonyms)
'cited vet unexpectedly european' is the wordplay.
'unexpectedly' indicates anagramming the letters.
'european' becomes 'E' (abbreviation e.g. EU).
'cited'+'vet'='citedvet'
'citedvet' anagrammed gives 'detectiv'.
'detectiv'+'e'='DETECTIVE'
(Other definitions for detective that I've seen before include "police officer" , "Public or private investigator" , "Criminal investigator" , "Expert solver of clues" , "Policeman, say" .)