What does the cryptic crossword clue "Probity not altogether necessary in valedictory notice (4)" mean?

The definition is "notice". The wordplay uses a hidden word. A hidden answer (‘not altogether necessary’) in ‘pr OBIT y’. The answer is OBIT.

Probity not altogether necessary in valedictory notice (4)

Guardian Cryptic #29387 | 13 Across | 2024-05-20 flower