Better boat seen by queen (6)
I believe the answer is:
punter
'better' is the definition.
(I know that better can be written as punter)
'boat seen by queen' is the wordplay.
'boat' becomes 'punt' (type of boat).
'seen by' means one lot of letters go next to another.
'queen' becomes 'ER' (short for Elizabeth Regina ie Queen Elizabeth).
'punt'+'er'='PUNTER'
(Other definitions for punter that I've seen before include "Informally, a customer or someone who bets" , "Person who bets" , "One betting; 4's prey (slang)" , "Better - rugby player - river boatman" , "Professional gambler; client (inf.)" .)