Definition of "foul"

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.

1944 November and December, A Former Pupil, “Some Memories of Crewe Works—II”, in Railway Magazine, page 342

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.

2013 June 29, “Unspontaneous combustion”, in The Economist, volume 407, number 8842, page 29

[…] Hast thou forgot / The foul witch Sycorax, who with age and envy / Was grown into a hoop? Hast thou forgot her?

1610–1611 (date written), William Shakespeare, “The Tempest”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene ii]

Who first seduced them to that foul revolt?

1667, John Milton, “Book I”, in Paradise Lost. […], London: […] [Samuel Simmons], […]; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873,

Let us, like merchants, show our foulest wares.

c. 1602, William Shakespeare, “The Tragedie of Troylus and Cressida”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene iii]

So foul a sky clears not without a storm.

c. 1596 (date written), William Shakespeare, “The Life and Death of King Iohn”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene ii]

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.

2015, Transportation Safety Board of Canada, Railway Investigation Report R13T0192

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.

1961 November, “Talking of Trains: Aircraft on rail tracks”, in Trains Illustrated, page 650

The Indian's heart was sore for his boat; it looked as if nothing could save her. She was drifting more slowly now, her propeller fouled in kelp.

1941, Emily Carr, chapter 18, in Klee Wyck‎

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.

1963 July, “News and Comment: The future of coal by rail”, in Modern Railways, page 5

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.

2011 December 10, Arindam Rej, “Norwich 4 - 2 Newcastle”, in BBC Sport‎