be a dab hand at something/at doing something

be a dab hand

To be skilled in a particular area. Primarily heard in UK, Australia. Amanda can fix that hole in your blouse—she's a dab hand at sewing.
See also: dab, hand
Farlex Dictionary of Idioms.

be a dab hand at

be expert at.
Dab in this sense is recorded since the late 17th century, but its origin is unknown.
1998 Bookseller Stephanie Cabot…is apparently a dab hand at milking cows, according to one of those mystifying diary items in Skateboarders' Weekly.
See also: dab, hand
Farlex Partner Idioms Dictionary

be a dab ˈhand at something/at doing something

(British English, informal) be very good at doing something: Ask Neil to do it — he’s a dab hand at carpentry.
See also: dab, hand, something
Farlex Partner Idioms Dictionary
See also:
  • be a dab hand
  • be a dab hand at
  • a dab hand
  • dab
  • can (do something) on (one's) ear
  • dab off
  • smack-dab
  • dab on them folks
  • make good as
  • make good as (something)