What does the suffix -ist mean in the word optimist? Among the three sisters, the optimist had the brightest outlook

i would need the available options to be listed to give you an answer.

i am a strong (insert gender here) my father and his brother were to, they were killed not by the cold, not by the bears or wolves that roam our streets at night, but by the   bolsheviks. we must stand up and fight communism or we all end up dead, starved dehydrated, enslaved. the time is now we must fight. lenin is a dangerous man but he can be stopped. so my comrades we shall siege there weapons tonight on ward. (rides away with ak(not invented yet) and sword in hand while on bear into snowstorm)