dead of winter

beat a dead horse

To persist or continue far beyond any purpose, interest or reason.

Brown bread

[Cockney slang]dead

buy straw hats in winter

Of stocks, to buy when both demand and price are low, so as to sell when demand and price are high.

come back from the dead

To experience a resurgence after one's productive years are assumed to have ended.

dead 'n' buried

Contraction of dead and buried.

dead air

An unintended interruption in a broadcast during which nothing is transmitted: a silent period on radio or a silent period with no picture on television.

dead and buried

Of an issue, moot, passed, irrelevant, forgotten.

dead asleep

Sleeping in a deep sleep