stillCan't you just sit still for a moment?
motionlessHe stood motionless when he saw the snake.
not move a muscleHe sat there the whole time and didn't move a muscle.
stock-stillShe stood stock-still as soon as she saw the bear.
immobileShe sat immobile, wondering what to do next.
inertThe inert figure of a man could be seen lying in front of the car.
steadyI'll hold the boat steady while you climb in.
frozenHe stood frozen in place as he watched the house burn.