What is the meaning of atypical?

adjective

• Not representative of a group, class, or type.
  • usage: "a group that is atypical of the target audience"; "a class of atypical mosses"; "atypical behavior is not the accepted type of response that we expect from children"
  • synonyms: untypical
• Deviating from normal expectations; somewhat odd, strange, or abnormal.
  • usage: "these days large families are atypical"; "atypical clinical findings"; "atypical pneumonia"; "highly irregular behavior"
  • synonyms: irregular