oddball

Etymology

Compound of odd + ball. Attested since the 1940s, with the adjective appearing earlier than the noun.

noun

1. An eccentric or unusual person.
   Miss Quinn thought that Oswald spoke Russian well in view of his lack of formal training; she found the evening uninteresting. Donovan, with whom she had a date later, testified that she told him that Oswald was “kind of an oddball.” 1964, Earl Warren et al., Report of the President's Commission on the Assassination of President John F. Kennedy, page 685
   "She's different, mister. A real oddball, if you know what I mean. But your little girl would love her. All kids love the Doll Lady." 1989, Maris Soule, Storybook Hero, page 5
2. (neuroscience) A deviant stimulus that appears among repetitive stimuli during an experiment, to trigger an event-related potential in the participant.

adj

1. Exotic, not mainstream.
   An oddball word processor, for example, might never be supported by such helpful tools as spelling checkers, indexing programs, footnote utilities,... 1984, Steven K. Roberts, The Complete Guide to Microsystem Management