These words refer to stretches of land in which soil and water, often stagnant, are intermingled with no clear demarcations, a situation that results in unstable footing or presents resistance to navigation. Marsh indicates a shallow, stagnant expanse of standing water enclosed by wet and treacherous soil: a track that swooped in a wide circle to avoid the marsh . Swamp suggests a large marsh that has some patches mainly of wet soil and others mainly of muddy water: They pushed through the swamp in a flat-bottomed boat, but frequently had to get out and drag the boat. Both marsh and swamp may suggest the presence of vegetation such as grass or even trees; swamp , particularly, might suggest an almost impassable overgrowth: an impenetrable mangrove swamp .

Fen specifically suggests a swamp overgrown with vegetation and filled with fetid water, but the word is not commonly used here.

• Hereward the Wake’s stronghold in the fens of Ely.

Morass indicates low-lying, soft, wet ground in which one can be easily mired, and is now more often used metaphorically for entangling complications into which it is easy to be drawn but from which it is difficult to escape, once involved: a morass of work that threatened to overwhelm him.

The remaining words all suggest a marsh or swamp that has a specific locale and a particular set of topographic features. Everglade , used mostly in the United States, points to a low-lying subtropical swamp covered with tall grass: the Florida Everglades . Bayou , also American, indicates a marshy inlet or outlet of a lake or river; its root is a Louisiana French word borrowed from the Choctaw Indian word for a small stream: the bayous of the Mississippi delta. Paddy comes from the Malay, referring to flooded lowlands in the Orient where rice is grown: peasants working in the terraced rice paddies . Bog is dawn from an Irish word for soft, referring to wet, spongy soil that is overgrown with grass: peat bogs from which the Irish harvested a fuel for heating and cooking. Bog is the only one of these localized words that can apply more widely. In this case, it refers to soft, wet soil that provides only treacherous footing and from which it is difficult to extricate oneself; the metaphorical implications here are more clearly seen in the word’s verbal form: bogged down in another useless man-to-man talk with his father.