efficacious

Merriam-Webster's Word of the Day for June 12, 2024 is: efficacious ef-uh-KAY-shus adjective What It Means Efficacious is a formal word used to describe something—often a treatment, medicine, or remedy—that has the power to produce a desired result or effect. // Companies like to tout the number of efficacious natural ingredients in their beauty products. cynosure in Context “Baking soda is commonly used alongside detergent to fix stinky loads ... but washing soda is the typical go-to for most tough laundry jobs. Baking soda is gentler than washing soda, so it won’t be as efficacious.” — Leslie Corona, Real Simple Magazine, 29 Dec. 2023 Did You Know? If you guesstimate that efficacious is the effect of combining effective with the suffix -ious, you’re on the right track. Efficacious came to English from the Middle French word efficace (or that word’s Latin source, efficāc- or efficāx), meaning “effective.” (These words ultimately trace back to the Latin verb efficere, “to make, bring about, produce, carry out.”) English speakers added -ious to effectively create the word we know today. Efficacious is one of many, er, eff words that mean “producing or capable of producing a result.” Among its synonyms are the familiar adjectives effective and efficient. Efficacious is more formal than either of these; it’s often encountered in medical writing where it describes treatments, therapies, and drugs that produce their desired and intended effects in patients.