Slang - SearchInQ

Slang

Dictionary of English Slang and Colloquialisms of the UK

http://www.peevish.co.uk/slang/
A monster-sized dictionary of English slang and British colloquialisms (informal speech) currently used in the UK, listing over 4000 slang expressions.

Urban Dictionary

http://www.urbandictionary.com/
Slang dictionary that defines words used by people in American urban settings.