Chiefly British informal; used predicatively with 'at' to mean 'skilled, expert'.
Definitions
dabbernoun
A small tool used for applying or dabbing substances, such as ink or paint.
The artist used a dabber to apply the ink precisely onto the paper.
A device used in bingo games to mark numbers on cards.
She quickly marked her bingo card with a dabber as the numbers were called out.
A person who dabs; one who applies or consumes something by dabbing, especially in contexts such as printing, painting, or using cannabis concentrates.
As a seasoned dabber, he always keeps his tools clean.
dabadjective
Skilled or expert at a particular activity (usually followed by 'at').