unpowerful

adjective

1. having or exerting great power or force.
2. physically strong, as a person: a large, powerful athlete.
3. producing great physical effects, as a machine or a blow.
4. potent; efficacious: a powerful drug.
5. having great effectiveness, as a speech, speaker, description, reason, etc.
6. having great power, authority, or influence; mighty: a powerful nation.
7. Chiefly South Midland and Southern U.S. great in number or amount: a powerful lot of money.

adjective

1. having great power, force, potency, or effect
2. extremely effective or efficient in actiona powerful drug; a powerful lens
3. dialect large or greata powerful amount of trouble

adverb

4. dialect extremely; veryhe ran powerful fast

adj.c.1400, from power (n.) + -ful. Meaning “of great quality or number” is from 1811; colloquial sense of “exceedingly” (adv.) is from 1822. Related: Powerfully. Thornton (“American Glossary”) notes powerful as “Much used by common people in the sense of very,” along with monstrous and cites curious expressions such as devilish good, monstrous pretty (1799), dreadful polite, cruel pretty, abominable fine (1803), “or when a young lady admires a lap dog for being so vastly small and declares him prodigious handsome” (1799).