— Merriam-Webster, Daily Prompt
efficacious Adjective | ef-ih-KAY-shus Effective; capable of producing the desired result.
— Merriam-Webster, Daily Prompt
Use "efficacious" in a new journal entry.
Context
Used in a sentence: The new technique proved remarkably efficacious in solving the problem.
Journaling prompt: What’s a strategy or method you use that actually works?