What is the scientific word for NOT moving?

In physics,

There's no clearcut answer for this. Typically physicists speak of an objects momentum, velocity, speed, or energy when referring its motion, and likewise refer to an object as being motionless, still, or stationary for objects that aren't moving. The bold Words are what I would say are the most commonly used for "moving" and "not moving".

Motion is relative, though, and so there's no concrete or scientific way to designate motion. So, scientists don't say "the box is moving" instead they say "the box is moving with respect to the wall". To someone's point of view, the box isn't moving, but instead the wall is. the scientific Word is moving out lol

In zoology,

A sessile animal is one of several kinds of animals that are not able to move about, but are permanently attached to some substrate, such as a rock, a plant, or the hull of a ship.

The opposite of sessile is motile, able to move about. There are a huge number of more specific Words for various ways of moving -- ambulatory, free-swimming, etc.