What does the cryptic crossword clue "Sister about to confuse worker in leather (7)" mean?

The wordplay uses a container (one word inside another). ADDLE (synonym="confuse") in SR (synonym="SR") = SADDLER The answer is SADDLER.

Sister about to confuse worker in leather (7)

Guardian Cryptic #29254 | 19 Down | 2023-12-15 flower