What does it mean to nail the coffin shut or put a nail in the coffin?

So yeah what does it mean?What does it mean to nail the coffin shut or put a nail in the coffin?
same as saying tie all lose ends or put finishing touches to somethingWhat does it mean to nail the coffin shut or put a nail in the coffin?
Basically, a scenario comes along and you or the person decide to end said scenario. To ';put the nail in the coffin'; means that it's over and done with.


On a similar note, ';the final nail in the coffin'; means that bad things kept happening and the last thing to happen is the final nail. Sort of a combination of ';the straw that broke the camel's back'; and the saying you just asked about.
It does mean to finalize something. But it was also a used as a slang expression when someone would light up a cigarette-like - you are putting another nail in your coffin by smoking.
it means to ';finalize'; it....