What are the antonyms for EFFICACY?

Synonyms for EFFICACY

Usage Examples for EFFICACY

  1. To appreciate justly the intensity of their anxiety for the conversion of the heathen, we must keep in our minds the views then universally entertained of the merits and efficacy of mere formal communion with the Church, and the fatal consequences of not being within that communion. - "The Life of Columbus" by Arthur Helps
  2. In these days we need to keep fast hold of our belief in the efficacy of prayer for others and for ourselves. - "Expositions of Holy Scripture Genesis, Exodus, Leviticus and Numbers" by Alexander Maclaren