What does the cryptic crossword clue "A new prefix, one I prepared earlier? (3)" mean?

The definition is "A new prefix,". The wordplay uses an anagram. anagram of ONE = NEO; definition: "A new prefix," The answer is NEO.

A new prefix, one I prepared earlier? (3)

Guardian Cryptic #29048 | 25 Down | 2023-04-19 flower