toss-up

Từ điển Oxford Advanced Learner 8th

ˈtoss-up [toss-up toss-ups] BrE NAmE noun singular (informal)
a situation in which either of two choices, results, etc. is equally possible
•‘Have you decided on the colour yet?’ ‘ It's a toss-up between the blue and the green.’

• Từ đồng nghĩa / Synonyms:
  tossup, even chance