What does the cryptic crossword clue "Gloomy signal from one who knows the score? (8)" mean?

The definition is "Gloomy / signal from one who knows the score?". The wordplay uses a double definition. Double definition The answer is DOWNBEAT.

Gloomy signal from one who knows the score? (8)

Times Cryptic #28963 | 9 Down | 2024-07-08 flower