Tycoon (4)
'tycoon' is the definition.
(both can mean a rich person)
This is all the clue.
(Other definitions for mogul that I've seen before include "Magnate; mound of hard snow on a ski slope" , "Bashaw" , "bigwig" , "Tycoon -- ski slope mound" , "big shot" .)
'tycoon' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for magnate that I've seen before include "Important fellow" , "Mogul" , "Fat cat" , "Wealthy figure" , "Tycoon" .)
'tycoon' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for czar that I've seen before include "Despot" , "policy coordinator" , "person of great power" , "Pre-1917 Russian ruler" , "Russian ruler (alt. but not rare spelling)" .)