'Missionary' definitions:

Definition of 'missionary'

adjective

Relating to or connected to a religious mission [syn: missionary, missional]

noun

Someone who attempts to convert others to a particular doctrine or program

noun

Someone sent on a mission--especially a religious or charitable mission to a foreign country [syn: missionary, missioner]

From: GCIDE

Missionary \Mis"sion*ary\, n.; pl. Missionaries. [Cf. F. missionnaire. See Mission, n.] One who is sent on a mission; especially, one sent to propagate religion. --Swift. [1913 Webster]
Missionary apostolic, a Roman Catholic missionary sent by commission from the pope. [1913 Webster]

From: GCIDE

Missionary \Mis"sion*a*ry\, a. Of or pertaining to missions; as, a missionary meeting; a missionary fund. [1913 Webster]