Optimist and Rationalist

Optimist noun - A person disposed to take a favorable view of things.

Rationalist is an antonym for optimist.

Nearby Words: optimistic, optimism, optimistically, optimize, optimise

Rationalist noun - Someone who emphasizes observable facts and excludes metaphysical speculation about origins or ultimate causes.

Optimist is an antonym for rationalist in topics: skeptic, unbelieving.

Nearby Words: rational, rationalize, rationale, rationalise, rationality