What does the cryptic crossword clue "Overturn function of multinational organization (4)" mean?

The wordplay uses a charade (building blocks). UN (synonym="”multinational organisation”") + DO (synonym="DO") = UNDO The answer is UNDO.

Overturn function of multinational organization (4)

Guardian Cryptic #29369 | 12 Across | 2024-04-29 flower