word that goes beyond optimistic?

A few months ago my professor mentioned a word that essentially went beyond being optimistic... He said that optimistic people were simply hopeful, but this adjective that he mentioned meant someone who takes action to make the change that they envision.

I wrote down the word down as meadialistic (that was clearly wrong) I tried to google so many different ways it could be spelled, but I think I was so off in the spelling that I won't be able to find the answer on my own... Any help would be appreciated

thank you!

Perhaps the answer is bullish. Optimism implies hope that something will turn out for the best without actually implementing action based on that belief, whereas bullish implies that one is hopeful/confident to the point that they will place their money (take definitive action) based on that level of hope/confidence.