What does the cryptic crossword clue "Broadcast hammered — that's beyond dispute (8)" mean?

The wordplay uses a charade (building blocks). AIR (synonym="broadcast") + TIGHT (synonym="hammered = drunk") = AIRTIGHT The answer is AIRTIGHT.

Broadcast hammered — that's beyond dispute (8)

Guardian Cryptic #29198 | 11 Across | 2023-10-11 flower