YOLO, Splendiferous Among 500 Words Added to Dictionary

The English language is an ever evolving beast. From new words and phrases being created out of necessity like automobile, internet and needle drop (records), to new meanings like awful and awesome were once synonymous with each other, used to denote reverential fear, before awful took on the negative aspects of the meaning, while awesome took on the positive aspects.

As such, the Oxford English Dictionary is constantly adding new words, altering meanings or senses depending on the contemporaneous usage. The O.E.D. has added over 500 new words, sub-meanings and senses of words (i.e. a word that was once a noun, is now also a verb). You can see the full list of new words here, but a few of the highlights:

• Dahlesque, an adjective meaning "resembling or characteristic of the works of Roald Dahl."
  This was a nice way to honor the beloved author on his 100th birthday, he gets a word! Several, in fact, as scrumdiddlyumptious, human bean, Oompa Loompa, and splendiferous were all added to the pages of the O.E.D. after previously appearing in the pages of Dahl's novels and stories.
• a few colloquialisms, like fuhgeddaboudit described as an interjection "In representations of regional speech (associated especially with New York and New Jersey): ‘forget about it’, used to indicate that a suggested scenario is unlikely or undesirable;" and jagoff, a noun, "(chiefly in western Pennsylvania) a stupid, irritating, or contemptible person."
• YOLO has been defined as "You only live once (expressing the view that one should make the most of the present moment without worrying about the future, and often used as a rationale for impulsive or reckless behavior)"
• 'Merica got a nod, being defined as "America (used especially to emphasize qualities regarded as stereotypically American, such as materialism or fervent patriotism)"