What does the cryptic crossword clue "Reward for man once incarcerated in Reading? (5)" mean?

The definition is "Reward for man once incarcerated in Reading?". The wordplay uses a double definition. Double definition The answer is OSCAR.

Reward for man once incarcerated in Reading? (5)

Guardian Cryptic #29078 | 10 Across | 2023-05-24 flower