Pronunciation: (fif'tē-fif'tē),[key] —adj. equally good and bad, likely and unlikely, favorable and unfavorable, etc.: a fifty-fifty chance of winning.
—adv. 1. in an evenly or equally divided way: The board voted fifty-fifty on the merger. 2. go fifty-fifty (on), to share equally in the cost, responsibility, or profits (of): We went fifty-fifty on the dinner check.Also,50-50.