סָגוּר!
סָגוּר
means literally closed, but it is also used informally to mean decided and confirmed, as in:
אָז נִפָּגֵשׁ בִּשְׂדֵה הַתְּעוּפָה. סָגוּר!
So we’ll meet at the airport. Done deal!
As does its English equivalent, !סגור comes from the business expression לִסְגּוֹר עִסְקָה – to close a deal 
Used informally, סגור can also mean sure, as in:
אֲנִי לֹא סְגוּרה עַל זֶה.
I (a female) am not sure about this.