Why doesn’t “decider” mean the same as “decision maker”?

It’s all in the language. Most dictionaries say that a “decider” is the game, set, match, heat, whatever, that decides a contest between individual competitors or teams. Some of the dictionaries allow a second meaning: ‘a person that decides’. But if that usage was widely accepted, authors of books and articles on decision making would use it, as it’s less cumbersome. But I have read volumes on the subject, and they don’t!

So “decider” is a passive term. This is in sharp contrast to the normal verb/noun relationship, which is overwhelmingly active:

  • Do:doer
  • Maker:maker
  • Run:runner
  • Act: actor
  • Sing:singer
  • Lead:leader
  • Manage:Manager
  • and so on

Is this because the people who shape language instinctively understand that there’s nothing simple and finite about deciding? It’s an interesting theory, but we have no problem with parallel examples, like think:thinker or indeed with diagnose:diagnostician or analyse:analyst, even if the endings are different.

The French are straightforward: decider:decideur. By contrast the Spanish talk about taking decisions: tomar decisiones

I’m convinced that there is no coincidence in the language and usage in English. We use a complicated construction, because decision making is acknowledged to be a complicated process. 

“Decider” sounds just too elementary to do justice to an iterative and sophisticated activity.