adj. foul·er, foul·est
a. Offensive to the senses; revolting: "a foul little creature with greedy eyes and slobbering mouth" (J.R.R. Tolkien).
b. Having a bad odor or taste: foul breath; food that tasted foul.
c. Rotten or putrid: foul meat.
a. Containing dirt, impurities, or other foreign matter; foul water.
b. Clogged or bestrewn with unwanted material: The bay is foul with old sunken vessels.
c. Overgrown or encrusted with weeds, barnacles, or other organisms. Used of a ship's bottom.
d. Entangled or enwrapped: a foul anchor.
a. Morally detestable; wicked: foul deeds.
b. Vulgar or obscene: foul language.
c. Violating accepted standards or rules; dishonorable: used foul means to gain power.
a. Very disagreeable or displeasing; horrid: a foul movie.
b. Inclement or unfavorable: in fair weather or foul.
c. Irritable or upset: in a foul mood.
a. Sports Contrary to the rules of a game or sport: a foul boxing punch.
b. Baseball Outside the foul lines: a foul fly ball.
6. Marked with editorial changes or corrections: foul copy.
7. Archaic Ugly; unattractive.
1. Abbr. F
a. Sports An infraction or a violation of the rules of play.
b. Baseball A foul ball.
2. An entanglement or a collision.
3. An instance of clogging or obstructing.
4. A foul copy of a document.
In a foul manner.
v. fouled, foul·ing, fouls
1. To make dirty or foul; pollute. See Synonyms at contaminate.
2. To bring into dishonor; besmirch.
3. To clog or obstruct.
4. To entangle or catch (a rope, for example).
5. To encrust (a ship's hull) with foreign matter, such as barnacles.
a. Sports To commit a foul against.
b. Baseball To hit (a ball) outside the foul lines.
1. To become foul.
a. Sports To commit a foul.
b. Baseball To hit a ball outside the foul lines: fouled twice and then struck out; fouled out to the catcher.
3. To become entangled or twisted: The anchor line fouled on a rock.
4. To become clogged or obstructed.
Sports To be put out of a game for exceeding the number of permissible fouls.
To blunder or cause to blunder because of mistakes or poor judgment.
[Middle English, from Old English fūl; see p- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.