Francis Grose 
1811 Dictionary of the Vulgar Tongue 

Throughout history, most dictionaries have served the purpose of preserving the purity of the language, usually preferring the erudite vocabulary of the affluent upper classes to the salty, constantly evolving slang of their working-class counterparts. That began to change in the early modern period, when several innovative lexicographers began publishing collections of slang terms used by particular subcultures, such as criminals. According to scholars, Francis Grose's Dictionary of the Vulgar Tongue is one of the most important and complete of these early slang dictionaries. Spend some time with this fascinating volume to learn the slang definitions of words and phrases like "poisoned" (pregnant), "shooting the cat" (vomiting after excess alcohol consumption), and "snoozing ken" (a brothel).