mistake

an unforgivable mistake

an unimportant mistake

a mistake due to carelessness

The mistake is not very serious.

He made that mistake unconsciously.

He made this mistake by accident.

The mistake is being righted.

a calamitous mistake

an egregious mistake

penitent about his mistake

His mistake is quite unaccountable.

Some mistakes are unavoidable.

one mistake and you're toast.

it is understandable that mistakes occur sometimes.

Take care that no mistakes be made.

What a curious mistake!

Two mistakes are allowable in this game.

You made a mistake at the outset.

He may want to ponder his mistakes instead.

So they always make the same mistake again and again.

You all are making a gigantic mistake.

In hindsight, the cigar was a mistake.

I hear a lot of people make that mistake and go in underprepared.

Morty But they made a big mistake this time, Morty.

Secondly, they will never correct your mistakes.

" ... the strike was a tragic mistake" .

They were desperate to find a mistake!