The word geek is a slang term originally used to describe eccentric or non-mainstream people; in current use, the word typically connotes an expert or enthusiast obsessed with a hobby or intellectual pursuit. In the past, it had a generally pejorative meaning of a "peculiar person, especially one who is perceived to be overly intellectual, unfashionable, boring, or socially awkward". In the 21st century, it was reclaimed and used by many people, especially members of some fandoms, as a positive term.

Some use the term self-referentially without malice or as a source of pride, often referring simply to "someone who is interested in a subject (usually intellectual or complex) for its own sake".