What does the cryptic crossword clue "Most careless broadcast showing symbol (7,5)" mean?

The definition is "symbol". The wordplay uses an anagram. anagram of MOST + CARELESS = MALTESECROSS; definition: "symbol" The answer is MALTESECROSS.

Most careless broadcast showing symbol (7,5)

Daily Mail Cryptic #17002 | 10 Down | 2023-01-02 flower