(exclamatory phrase) a playful indication of surprise, misfortune, or insult
popularized by
Tracy Morgan of Saturday Night Live, OH SNAP is seemingly derivative of
oh no you didn't where an insulted person, for example a guest of Jerry Springer or often a spunky African American woman contends the insult being made against him/her. While derivative of "oh no you di-int," OH SNAP has more of an emphasis on playfulness and can be said by people other than those being insulted.
see also:
OH ZIP