Bigwig's arrest reflected personal problem (5)
I believe the answer is:
nabob
'bigwig's' is the definition.
(thesaurus)
'arrest reflected personal problem' is the wordplay.
'arrest' becomes 'nab' ('nab' can be a synonym of 'arrest').
'reflected' says the letters should be written backwards.
'personal problem' becomes 'bo' (informal abbreviation for body odour).
'bo' backwards is 'ob'.
'nab'+'ob'='NABOB'
(Other definitions for nabob that I've seen before include "very wealthy man" , "moneybags" , "Fat cat: governor in India during the Mogul empire" , "Powerful man" , "Magnate; formerly one with Eastern wealth" .)