know (one's) beans

To be knowledgable about and/or very familiar with something. I had no idea you were such a good piano player—you really know your beans!

Name	Pronounced	Usage
Dejan	-	Serbian, Croatian, Slovene, Macedonian
Gallchobhar	-	Irish (Rare)
HalİM	-	Turkish
Gobind	-	Indian (Sikh), Hindi
IonatÁN	-	Irish
Alic	['ælik]