Since I had an earlier ask about slang, I thought I’d pull together a few resources:

Historical Dictionary of American Slang - allows you to search by year

Slang Terms for Sex (And Related F*ckery) - Bow chicka wah wah

Medieval Slang Terms and Terminology - PDF File (Use these sparingly)

Shakespearean Slang and Sexual Language

Elizabethan Slang and Terminology

Victorian Slang Terms - Again, use sparingly

1700s UK Slang Terminology

Military Slang (Revolutionary War Era)

Slang From Colonial America

Civil War Era Slang

1920s Slang

Great Depression Era Slang

1940s Slang

1950s Slang

1960s Slang

1970s Slang

1980s Slang

1990s Slang