- The definition of powerful is having a lot of strength, authority or force.
An example of something powerful is a violent storm that knocks down many trees and electrical lines.
- Having or capable of exerting power.
- Effective or potent: a powerful drug.
- Chiefly Upper Southern US Great: “[Everybody had] a powerful lot to say about faith and good works and free grace &ellipsis; and I don't know what all” (Mark Twain).
adverbChiefly Upper Southern US
(comparative powerfuller or more powerful, superlative powerfullest or most powerful)