A golfer's assistant is called a caddy. A caddy is paid by golfer. Most professional golfers have caddies.
A 'scratch golfer' is the name given to a golfer whose handicap is zero.
Duffer
duffer
Caddy.
An Expert Aviator is called an "Ace".
A bully expert is called a bullnation
A cultures expert is called an ethnologist.
what ia an expert pilot called
Caddy these guys only really help professional golfers that are on the tour
A grammar expert is called a grammatician or a grammarian.
Expert advice or expert guidance.