What does the cryptic crossword clue "Form bad pathogen (8)" mean?

The definition is "F or m". The wordplay uses an anagram. anagram of PATHOGEN ("pathogen") [anagram: "Form"] = HEPTAGON The answer is HEPTAGON.

Form bad pathogen (8)

Independent Cryptic #11860 | 23 Across | 2024-10-14 flower