Which tool is primarily used for cutting hair?

The primary tool used for cutting hair is scissors. Scissors are versatile and allow for precise cuts, enabling both blunt cuts and texturizing techniques depending on the stylist's technique and the desired outcome. They come in various sizes and shapes, which can be chosen based on the specific cutting needs, such as the thickness of the hair or the style being achieved.

Clippers are often used for shorter styles and can give a uniform length quickly but may not provide the subtlety and precision that scissors can. Thinning shears, while effective for removing bulk or creating texture, are not designed for primary cutting but rather for refining styles. Razor blades are also used for texturizing and layering hair but are generally not the go-to tool for standard haircuts as they can create a different texture and finish compared to scissors.

Thus, scissors stand out as the fundamental tool for a wide range of hair cutting techniques, making them the correct answer in this context.