They are all new words. The Oxford American Dictionary tracks the use of such words, and if they ever get off the ground, so to speak, they get added to the list of official words.
NPR recently interviewed Erin McKean of the Oxford American Dictionary, and she explained the definition of these words. “Cromulent,” for example, means “perfectly acceptable.” “Lifehacking” means “making your life more efficient.”
I think “truthiness” is my favorite. It means “the actual facts don’t matter.” Or “you wish so much that something were true that you act as if it’s true.” We probably all have our pet opinions that we hold, not because of their real truth, but because of their truthiness. What is yours?