Synonyms for efficacy

 Here are several synonyms for efficacy, categorized by nuance:

Most Common Synonyms:

• Effectiveness: This is the most direct and frequently used synonym.
• Efficiency: Emphasizes achieving the result with minimal waste of time, energy, or resources.
• Potency: Suggests a strong ability to produce an effect.

Other Strong Synonyms:

• Capability: Focuses on the inherent ability to do something successfully.
• Productiveness: Highlights the ability to generate results or output.
• Success: Emphasizes achieving the desired outcome.
• Value: Suggests that something is useful and produces a positive result.
• Usefulness: Similar to value, highlighting the practical application and positive outcome.
• Virtue: Can imply a positive quality that makes something effective.
• Power: Similar to potency, suggesting a strong force or ability to produce results.

More Formal Synonyms:

• Efficaciousness: A more formal version of efficacy.
• Effectualness: Similar to effectiveness, but sometimes implies a more complete or decisive effect.
• Efficacity: An older, less common form of efficacy.

Synonyms emphasizing ability:

• Ability
• Capacity
• Competence

Synonyms emphasizing positive outcome:

• Benefit
• Advantage
• Profit

Synonyms emphasizing strength:

• Force
• Strength
• Vigor

The best synonym to use will depend on the specific context and the shade of meaning you want to convey.