What does the cryptic crossword clue "When to cut green targets for idiot (7)" mean?

The wordplay uses a deletion. AS (synonym="=when, as conjunction") in JACKS (synonym="=green targets, on bowling") = JACKASS The answer is JACKASS.

When to cut green targets for idiot (7)

Independent Cryptic #11850 | 4 Across | 2024-10-02 flower