Dictionary:

humanist

  (hyū'mə-nĭst)

1. A believer in the principles of humanism.
2. One who is concerned with the interests and welfare of humans.
3. 1. A classical scholar.
   2. A student of the liberal arts.
4. Humanist A Renaissance scholar devoted to Humanism.

The noun has 2 meanings:

Meaning #1: a classical scholar or student of the liberal arts

Meaning #2: an advocate of the principles of humanism

The adjective humanist has 4 meanings:

Meaning #1: of or pertaining to Renaissance humanism
  Synonym: humanistic
  Pertains to noun: humanism (meaning #3)

Meaning #2: of or pertaining to a philosophy asserting human dignity and man's capacity for fulfillment through reason and scientific method and often rejecting religion
  Synonym: humanistic
  Pertains to noun: humanism (meaning #2)

Meaning #3: pertaining to or concerned with the humanities
  Synonyms: humanistic, humane
  Pertains to noun: humanities (meaning #1)

Meaning #4: marked by humanistic values and devotion to human welfare
  Synonyms: human-centered, humanistic, humanitarian