Magnate not coy in flotation? (6)
I believe the answer is:
Here is my best explanation:
'magnate' is the definition.
(I've seen this before)
'not coy in flotation?' is the wordplay.
'in flotation?' indicates anagramming the letters (I've seen 'in flotation' mean this).
'notcoy' is an anagram of 'TYCOON'.
(Other definitions for tycoon that I've seen before include "Not coy? (anag)", "Rich businessperson", "Entrepreneur", "Big businessman", "Very wealthy businessman", "Big cheese in business", "Wealthy businessman", "Wealthy magnate", "See 2" and "A business magnate or wealthy industrialist".)