Definitions of quiescent:

• adjective:   marked by a state of tranquil repose

  Example: "The quiescent melancholy of the town"

• adjective:   causing no symptoms

  Example: "A quiescent tumor"

• adjective:   being quiet or still or inactive
• adjective:   not active or activated

  Example: "The quiescent level of centimeter wave-length solar radiation"