Thayer's Greek Lexicon

 1. steadfastness, constancy, endurance
  1) in the NT the characteristic of a man who is not swerved from
his deliberate purpose and his loyalty to faith and piety by
even the greatest trials and sufferings
  2) patiently, and steadfastly
2. a patient, steadfast waiting for
3. a patient enduring, sustaining, perseverance

For Synonyms see entry G5861