What haircutting tool is primarily used to cut blunt or straight lines in hair?

The primary tool used for cutting blunt or straight lines in hair is haircutting shears. These shears have a straight edge and are designed specifically for creating clean, even cuts, which results in well-defined shapes and styles. Haircutting shears allow for precision and control when cutting hair, making them ideal for various styles that require a sharp, straight line, such as bobs or a blunt cut.

In contrast, thinning shears are used to reduce bulk and add texture, while texturizing shears serve a similar purpose, helping to create movement and soft edges. A razor, on the other hand, is typically used for more textured or layered cuts, providing a softer finish rather than a blunt edge. Each of these tools has its specific purpose, making haircutting shears the best choice for achieving blunt lines.