(often Apostle) an early Christian teacher sent out to preach the gospel, esp one of the group made up of Jesus's original twelve disciples and Paul
any Christian missionary who was the first to preach Christianity in a place or among a people
an advocate, early exponent, or ardent supporter of a system, movement, etc
Gandhi, a noted apostle of passive resistance as a means of protest
an early apostle of Dadaism
apostleship noun
[Middle English from Old French apostle, or Old English apostol, both from late Latin apostolus, from Greek apostolos messenger, from apostellein to send away]