Slough of Despond

Slough of Despond, a deep bog in the “Pilgrim's Progress,” into which Christian sinks under the weight of his sins and his sense of their guilt.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)

Slop, Doctor * Slovaks
[wait for the fun]
Slavs
Slawkenbergius
Sleeping Beauty
Sleipnir
Sleswick-Holstein
Slick, Sam
Sligo
Sloane, Sir Hans
Slöjd
Slop, Doctor
Slough of Despond
Slovaks
Slovenians
Sly, Christopher
Smart, Christopher
Smeaton, John
Smectymnuus
Smelfungus
Smiles, Samuel
Smith, Adam
Smith, Alexander