toss-up
US /ˈtɑːs ʌp/
UK /ˈtɑːs ʌp/

1.
belli değil, başabaş, eşit şans
a situation in which either of two choices or results is equally possible and it is impossible to predict which will happen
:
•
It's a toss-up whether she'll get the job or not.
İşi alıp almayacağı belli değil.
•
The election is a real toss-up between the two main candidates.
Seçim, iki ana aday arasında gerçek bir başabaş mücadele.