What does the cryptic crossword clue "p or n? (non-clue, possibly) (7)" mean?

The wordplay uses an anagram. anagram of (NON-CLUE, = NUCLEON The answer is NUCLEON.

p or n? (non-clue, possibly) (7)

Guardian Cryptic #21681 | 11 Across | 1999-09-03 flower