Rationalist

noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    A person who follows the philosophy of rationalism.

    "“He says,” replied Lord Peter, “that he believes Hannah to be a sincerely religious woman. He has sat beside her in chapel and shared her hymn-book.” “But that may be the merest hypocrisy,” said Miss Murchison, rather warmly, for she was militantly rationalist. “I don’t trust these unctuous people.”"

  2. 2
    someone who emphasizes observable facts and excludes metaphysical speculation about origins or ultimate causes wordnet
  3. 3
    A member of the rationalist community.

    "Some rationalists were in touch with Oxford philosophers, including Toby Ord and William MacAskill, the founders of the effective-altruism movement, which studied how to do the most good for humanity (and, by extension, how to avoid ending it)."

Adjective
  1. 1
    of or relating to or characteristic of rationalism wordnet

Synonyms

All synonyms
adherentphilosopherpositivistpositivistsophistthinker

Example

More examples

"“He says,” replied Lord Peter, “that he believes Hannah to be a sincerely religious woman. He has sat beside her in chapel and shared her hymn-book.” “But that may be the merest hypocrisy,” said Miss Murchison, rather warmly, for she was militantly rationalist. “I don’t trust these unctuous people.”"

Etymology

From Middle French rationaliste; rational + -ist.

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.