What does the cryptic crossword clue "Partygate in magistrate's office (6)" mean?

The wordplay uses a charade (building blocks). DO (synonym="=party") + GATE (synonym="GATE") = DOGATE The answer is DOGATE.

Partygate in magistrate's office (6)

Independent Cryptic #11706 | 20 Across | 2024-04-17 flower