Stationary or fixed (6)
I believe the answer is:
static
This clue is a double definition.
'stationary' is the first definition.
(I've seen this before)
'fixed' is the second definition.
(I've seen this before)
(Other definitions for static that I've seen before include "Constant interference" , "Not active or moving" , "Lacking movement or action" , "Noise caused by electrical interferance" , "Still, not moving" .)