Thayer's Greek Lexicon

 1. to prophesy, to be a prophet, speak forth by divine inspirations,
to predict
  1) to prophesy
  2) with the idea of foretelling future events pertaining esp.
to the kingdom of God
  3) to utter forth, declare, a thing which can only be known
by divine revelation
  4) to break forth under sudden impulse in lofty discourse or
praise of the divine counsels
1d1. under like prompting, to teach, refute, reprove, admonish,
comfort others
  5) to act as a prophet, discharge the prophetic office