What does the cryptic crossword clue "Mug up on bank's charter? (6)" mean?

The definition is "charter". The wordplay uses a reversal. ROB (reversal="steal; mug") + ROW (synonym="a bank") = BORROW The answer is BORROW.

Mug up on bank's charter? (6)

Independent Cryptic #12074 | 22 Down | 2025-06-20 flower