Covered with, or containing unclean matter; dirty.
This cloth is too foul to use as a duster.
His foul hands got dirt all over the kitchen.
The air was so foul nobody could breathe.
A ship's bottom is foul when overgrown with barnacles
A well is foul with polluted water.
1944 November and December, A Former Pupil, “Some Memories of Crewe Works—II”, in Railway Magazine, page 342:
It was, however, most interesting work, and the moulders themselves were a decent crowd, never tired of making jokes about themselves such as the hoary one that moulders did not live long, which however ran counter to the other one that no germs could live in a foundry—the atmosphere was too foul.
Since the mid-1980s, when Indonesia first began to clear its bountiful forests on an industrial scale in favour of lucrative palm-oil plantations, “haze” has become an almost annual occurrence in South-East Asia. The cheapest way to clear logged woodland is to burn it, producing an acrid cloud of foul white smoke that, carried by the wind, can cover hundreds, or even thousands, of square miles.
[…]Hast thou forgot / The foul witch Sycorax, who with age and envy / Was grown into a hoop? Hast thou forgot her?
1667, John Milton, “Book I”, in Paradise Lost.[…], London: […] [Samuel Simmons], and are to be sold by Peter Parker[…]; [a]nd by Robert Boulter[…]; [a]nd Matthias Walker,[…], →OCLC; republished as Paradise Lost in Ten Books:[…], London: Basil Montagu Pickering[…], 1873, →OCLC:
Cultural norms and social rules regulate whether someone can be among others or will be isolated, whether the sick will be considered foul or acceptable, and whether they are to be pitied or censured.
The bus had stopped just foul of the north track at the Erindale Station Road public railway crossing[…] With the bus stationary, but still foul of the north track, the train struck one of its front mirrors.
The translations below need to be checked and inserted above into the appropriate translation tables. See instructions at Wiktionary:Entry layout § Translations.
1961 November, “Talking of Trains: Aircraft on rail tracks”, in Trains Illustrated, page 650:
As a result of the accident at Southend Airport when a Hermes aircraft overshot the runway and fouled the down Shenfield to Southend Victoria line between Rochford and Prittlewell, the Eastern Region is considering warning arrangements, which have already been provided on some lines running past aerodromes.
1963 July, “News and Comment: The future of coal by rail”, in Modern Railways, page 5:
The full capacity, however, requires a hopper of a size that takes the wagon body up to 11ft 11½in above rail level, which would foul many existing colliery screens.
(sports) A breach of the rules of a game, especially one involving inappropriate contact with an opposing player in order to gain an advantage; for example, tripping someone up in soccer, or contact of any kind in basketball.
2011 December 10, Arindam Rej, “Norwich 4 - 2 Newcastle”, in BBC Sport[3]:
A second Norwich goal in four minutes arrived after some dire Newcastle defending. Gosling gave the ball away with a sloppy back-pass, allowing Crofts to curl in a cross that the unmarked Morison powered in with a firm, 12-yard header. Gosling's plight worsened when he was soon shown a red card for a foul on Martin.
(bowling) A (usually accidental) contact between a bowler and the lane before the bowler has released the ball.
(baseball) A foul ball, a ball which has been hit outside of the base lines.