1. Something designed to deceive or mislead; hoax; fraud.
2. A person who passes him/herself off as something that he/she is not; an imposter.
3. An attitude of pretense or deception.
4. Nonsense; drivel.
As a verb, it means to deceive or trick.
Etymology: Became popular in the early 1750s, but no one seems to know how the word started.
Also the title of my favorite episode of The X-Files.