This idiom or expression means:

Dying.
Not active.
Will be dead.
Heading in the direction of being dead.

If you say “He’s as good as dead,” it could mean any of the following:

He’s dying.
He’s not active.
He’ll die very soon.
He will be killed very soon.
If I see him again, he’ll be in trouble. Etc.

This idiom or expression means:

Nothing can be done.

When someone says “We’re dead in the water,” they mean something like “There’s nothing we can do.”

This idiom or expression refers to:

A man on death row walking to his execution.
A person who will most certainly be in trouble soon.
Someone who will definitely be losing his or her job.
An announcement that a man on death row is walking to his execution.

This idiom or expression like phrase means:

Cash.
Monetary bills.
Dollar bills, paper money in general.

A “Hot One” is a $1 bill.
A “Jackson” is a $20 bill.
A “Grant” is a $50 bill.
A “Benjamin” is a $100 bill, also called a “C-note”.

This idiom or expression like phrase is a polite way of referring to a person who is not living.

“Sitting on the dock of the bay” was performed by the late, great Otis Redding.

This idiom or expression means:

Exact duplicate.
Exact look alike.

I couldn't believe my eyes. She’s a dead ringer for your mother!!