slang has ever-changing continual and definition of words in informal conversation, often using references as a means of comparison or showing likeness. some slang has endured over the decades since its inception (i.e. cool) and some will only last a few years before being rendered obsolete or outdated (i.e. bling bling). slang can be born from any number of situations or ideas (the word slang itself has come to represent selling, especially of illegal drugs), and can be blunt or riddled with metaphor, and often quite profound.