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.
steadyI'll hold the boat steady while you climb in.
stationaryWe sat stationary in heavy traffic for close to an hour.
frozenHe stood frozen in place as he watched the house burn.