Definitions of atypical:

• adjective:   deviating from what is usual or common or to be expected; often somewhat odd or strange

  Example: "These days large families are atypical"

• adjective:   deviating from or not conforming to type

  Example: "Atypical behavior..not the accepted type of response that we expect from children- G.E.Gardner"

• adjective:   not conforming to type

  Example: "Showed atypical agility"