Tycoon, snooty type, entertains one on deck? (5)
I believe the answer is:
nabob
'tycoon' is the definition.
(thesaurus)
'snooty type entertains one on deck?' is the wordplay.
'snooty type' becomes 'nob' (term for an upper-class person).
'entertains' is an insertion indicator.
'one on deck?' becomes 'AB' (abbreviation for able seaman).
'nob' going around 'ab' is 'NABOB'.
(Other definitions for nabob that I've seen before include "very wealthy man" , "Rich British merchant in India" , "Fat cat: governor in India during the Mogul empire" , "Magnate; formerly one with Eastern wealth" , "Person of great wealth" .)