Definitions of shifting:

• noun:   the act of moving from one place to another

  Example: "His constant shifting disrupted the class"

• adjective:   continuously moving or changing from position or direction

  Example: "He drifted into the shifting crowd"

• adjective:   continuously varying

  Example: "Taffeta with shifting colors"

• adjective:   (of soil) unstable

  Example: "Shifting sands"