know a thing or two
To be knowledgeable about something. The phrase is usually used to indicate that one knows more about something than someone thinks. Hey, I know a thing or two about art—I was an art history major in college, you know!
know a thing or two
(about someone or something) Go to a thing or two (about someone or something).
know a thing or two
be experienced or shrewd. 1993 Rolling Stone Andy Shernoff …knows a thing or two about great glam punk.
know a thing or two (about somebody/something)
(informal) know a lot about somebody/something from your own experience: After ten years as a teacher, I know a thing or two about how children learn.‘How much do you know about computers?’ ‘Oh, I know a thing or two.’