Trump, dimwit gambler covered with tan he sprayed (2,3,6,4)
I believe the answer is:
go one better than
'trump' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'dimwit gambler covered with tan he sprayed' is the wordplay.
'dimwit' becomes 'goon' (I can't justify this - if you can you should give a lot more credence to this answer).
'gambler' becomes 'better' (someone who makes bets is a gambler).
'covered with' is an insertion indicator.
'sprayed' indicates anagramming the letters (I've seen this in other clues).
'tan'+'he'='tanhe'
'tanhe' is an anagram of 'ethan'.
'better' inserted inside 'ethan' is 'ebetterthan'.
'goon'+'ebetterthan'='GO ONE BETTER THAN'
Can you help me to learn more?