What does the cryptic crossword clue "Cast of no discernment is essential for those in theatre (15)" mean?

The wordplay uses an anagram. anagram of OF + NO + DISCERNMENT = INFORMEDCONSENT The answer is INFORMEDCONSENT.

Cast of no discernment is essential for those in theatre (15)

Independent Cryptic #11733 | 24 Across | 2024-05-18 flower