this is it

this is it

1. Used to indicate that something important has finally happened or is about to happen.
   • 1986, Caroline Richards, Sweet Country, page 6:

     Yesterday, when I heard that General Prats had resigned as Commander-in-Chief, I thought to myself, This is it. The Fascists have finally driven him out.

   • 2014, Patrick Tucker, Secrets of Screen Acting:

     This is it: the moment of truth. This is when the preparation and work of all contributors is finally put to the test.

   • 2017, Andrew M. Greeley, God in the Movies, page 20:

     In this cinematic epiphany Bridges has gone from panic and fear of crashing (“He can't steer, we're going down”) to a shock-induced realization of his own mortality (“This is it, the moment of your death”) to realizing the possibility of something like life after death ("I am not afraid, I have no fear").

2. Used to acknowledge the limits of something.
   • 1977, Bill Knott, The Craft of Fiction, page 6:

     Remember, the key here is that you know that this is it, the last copy; there will be no more chances to revise, no typist to complete this onerous task.

   • 2015, Phil Zuckerman, Faith No More: Why People Reject Religion, page 129:

     It makes me want to have more of an influence on the world while I'm here because this is it. This is my only shot.

   • 2019, Sreenivas Madhira, This is it: Yet another NDE? Or, is it just END?:

     “So,” completely resigned to a dreary world, “this is it? There is nothing to look forward to? We get just one life? It hardly seems worth it, doesn't it?”

   • 2021, Conor Creighton, This Is It:

     The key to happiness is recognising that, yes, this is it. You're all you have to work with and this moment is the only one you have any control over.

• that's all
• that's it
• this is the life

• “this is it”, in Merriam-Webster Online Dictionary
• “this is it” in Longman Dictionary of Contemporary English, Longman.