booked up

adjective2

1. •
   (slang) Well-read on a particular topic.

   • […] and we believe the day is usually the one on which the saint is supposed to have died; but this we cannot affirm, as we are not booked up in Roman sanctology. — 1875
2. •
   (slang) Extremely knowledgeable in a particular opening as a result of intensive study.

   • This line is not by any stretch of the imagination considered a critical line, but it does take the players out of mainstream theory, where Giri typically is hardcore booked up. — 2022