Open English Wordnet
Adjectives
(a)atypical, untypical, atypicnot representative of a group, class, or type“a class of atypical mosses”,
“atypical behavior is not the accepted type of response that we expect from children” (s)atypical, irregulardeviating from normal expectations; somewhat odd, strange, or abnormal“these days large families are atypical”,
“atypical clinical findings”,
“atypical pneumonia”,
“highly irregular behavior”