One given to fanciful ideas or theories; someone who theorizes or speculates.
Someone who espouses a particular ideology, particularly a political one.
Any of a group of philosophers who assert that true knowledge is obtained by faculties of the mind that transcend sensory experience; those who exalt intuition above empirical knowledge and ordinary mentation. Used in modern times of some post-Kantian German philosophers, and of the school of Emerson.
One who believes in transcendentalism.