Definitions of extraneous:

• adjective:   not essential

  Example: "The ballet struck me as extraneous and somewhat out of keeping with the rest of the play"

• adjective:   not pertinent to the matter under consideration

  Example: "An issue extraneous to the debate"

• adjective:   not belonging to that in which it is contained; introduced from an outside source

  Example: "Water free of extraneous matter"

• adjective:   coming from the outside

  Example: "Extraneous light in the camera spoiled the photograph"