One new prefix (3)
I believe the answer is:
neo
'one new prefix' is the definition.
(I've seen this in another clue)
'one new' is the wordplay.
'new' indicates an anagram.
'one' is an anagram of 'NEO'.
(Other definitions for neo that I've seen before include "New (suffix)" , "Prefix meaning new or recent" , "language" , "Prefix meaning new - try one" , "Prefix donating new" .)