What does the cryptic crossword clue "Old pirate misused instrument going through locks (9)" mean?

The wordplay uses an anagram. anagram of OLD (synonym="OLD") + PIRATE (synonym="PIRATE") = DEPILATOR The answer is DEPILATOR.

Old pirate misused instrument going through locks (9)

Guardian Cryptic #29264 | 11 Across | 2023-12-28 flower