The adjective effective describes things that are adequate to accomplish a purpose, or that produce the intended or expected result. But effective isn’t quite the same as effectual, efficacious, or efficient!

EFFECTIVE definition: 1. successful or achieving the results that you want: 2. (used about a treatment or drug) working…. Learn more.

Some common synonyms of effective are effectual, efficacious, and efficient. While all these words mean "producing or capable of producing a result," effective stresses the actual production of or the …

Effective and efficient are often confused, but they have slightly different meanings. If you are effective, you do a job properly; if you are efficient, you do it quickly and easily.

The adjective effective has many shades of meaning, but you'll usually see it describing something that's able to produce a desired goal. Effective traces back to the Latin word effectivus, from efficere, …

Effective, effectual, efficacious, efficient refer to that which is able to produce a (desired) effect. Effective is applied to that which has the power to, or which actually does, produce an effect: an effective …

Jan 20, 2026 · Adjective effective (comparative more effective, superlative most effective) Having the power to produce a required effect or effects.