Definition of "powerful"

The powerful grace that lies / In herbs, plants, stones, and their true qualities.

c. 1591–1595 (date written), William Shakespeare, “The Tragedie of Romeo and Ivliet”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene iii]

As soon as Julia returned with a constable, Timothy, who was on the point of exhaustion, prepared to give over to him gratefully. The newcomer turned out to be a powerful youngster, fully trained and eager to help, and he stripped off his tunic at once.

1963, Margery Allingham, chapter 19, in The China Governess‎

Dear Political ActivistsAll your chanting, marching, voting, picketing, boycotting and letter-writing will not change a thing; you will never right the wrongs of this world. The only thing your activity will accomplish is to make some of you feel better. Such activity makes powerless people feel useful, and provides them the illusion that they're making a difference. But it doesn't work. Nothing changes. The powerful keep the power. That's why they're called the powerful.

2004, George Carlin, “NOTHING CHANGES”, in When Will Jesus Bring the Pork Chops?‎, New York: Hyperion Books, page 106