What does the cryptic crossword clue "Not being affected by if it's open surprisingly (2,5,2)" mean?

The wordplay uses an anagram. anagram of IF + IT'S + OPEN = INSPITEOF The answer is INSPITEOF.

Not being affected by if it's open surprisingly (2,5,2)

Independent Cryptic #12043 | 12 Across | 2025-05-15 flower