determinator
/dɪˈtɜːrmɪneɪtər/
noun
- A person or thing that determines or decides something, especially in a decisive or forceful way.
- The weather will be the main determinator of whether we go hiking tomorrow.
- In the final round, the judge acted as the determinator of the winner.
- She was the determinator in the group, always making the final call on big decisions.