The phrase "straight as an arrow" is often used to mean that something or someone is completely linear, direct, and without any deviation or divergence. Some alternative phrases that can be used include "like a laser beam," "in a straight line," "dead straight," "point-blank," and "perfectly aligned." Another way to say it would be "as straight as a die" or "as straight as a ruler." Regardless of which phrase you use, all of these suggest a sense of precision, accuracy, and unwavering commitment to a certain direction or path, which can apply to a variety of contexts, from physical movements to mental focus.