What does the cryptic crossword clue "Football manager's season threatened with relegation? (12)" mean?

The wordplay uses a charade (building blocks). WINTER (synonym="WINTER") + BOTTOM (synonym="BOTTOM") = WINTERBOTTOM The answer is WINTERBOTTOM.

Football manager's season threatened with relegation? (12)

Times Cryptic #29119 | 12 Across | 2025-01-06 flower