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1. Not representative of a group, class, or type
   "a class of atypical mosses"; "atypical behaviour is not the accepted type of response that we expect from children"; "a group that is atypical of the target audience";
   - untypical
    
2. Deviating from normal expectations; somewhat odd, strange, or abnormal
   "these days large families are atypical"; "atypical clinical findings";
   - irregular

See also: abnormal, typicality, uncharacteristic, unnatural, unrepresentative

Antonym: typical

Encyclopedia: Atypical, Adjuvant & Potentiators Atypical, adjuvant and potentiators