Definition

The ability to produce a specific result or effect; how well something works.

Example

The efficacy of the new drug was tested in clinical trials.

Conversation

Have you heard about the new study on the efficacy of that herbal remedy?

Yeah, I read a bit about it, and it seems promising!

I wonder how they measured the efficacy compared to traditional treatments.

Good question! It’s always interesting to see how new methods stack up.

Synonyms & Antonyms

Root Explanation

Efficacy → It is formed from "efficax" (meaning effective) and the suffix "-cy" (meaning the state or quality of). The word "efficacy" refers to the quality of being effective or producing a desired result.

Memory Tip

Think of 'effective' to remember that 'efficacy' means the quality of being effective.

Visually Confused Words