oddball

An oddball is a person or thing that is conspicuously unusual or unconventional. In everyday language, an oddball may be described as quirky or eccentric; the label can be used neutrally, affectionately, or pejoratively depending on context. The term is formed from odd and ball, implying something that does not fit the expected pattern or shape. In common usage it can refer to a person, a situation, or an object that stands out from the norm. The plural is oddballs.

Beyond colloquial use, oddball has technical meanings in science. In psychology and neuroscience, the oddball paradigm is an experimental design in which participants respond to rare target stimuli interspersed with frequent standard stimuli. The rarity of the targets tends to evoke distinct neural responses, such as the P300 component of event-related potentials, and is used to study attention, perception, and memory. In statistics or data analysis, an 'oddball' can refer to an outlier—an observation that diverges markedly from the rest of the data.

In culture, oddball appears as a descriptor for unconventional characters and as the title or motif of various works, reflecting the idea of deviation from the ordinary. The word is widely understood in English-speaking regions and appears in journalism, education, and popular media as a light, informal label rather than a technical term. As with many slang terms, its connotations depend on tone, context, and intent.