Thayer's Greek Lexicon

 1. trusty, faithful
  1) of persons who show themselves faithful in the
transaction of business, the execution of commands, or
the discharge of official duties
  2) one who kept his plighted faith, worthy of trust
  3) that can be relied on
2. easily persuaded
  1) believing, confiding, trusting
  2) in the NT one who trusts in God's promises
2b1. one who is convinced that Jesus has been raised from the dead
2b2. one who has become convinced that Jesus is the Messiah
and author of salvation