Which type of haircuts is not authorized for soldiers?

The type of haircuts that is not authorized for soldiers is extreme haircuts. In the Army, the regulation regarding haircuts emphasizes that military personnel maintain a professional appearance that embodies discipline and order. Extreme haircuts can include styles that are unconventional, overly flamboyant, or that draw excessive attention to the individual, which is contrary to the uniform and cohesive appearance required in military service.

In contrast, military-style haircuts, short buzz cuts, and standard civilian haircuts are permissible as they align with the established regulations regarding uniformity and professionalism. Military-style haircuts are specifically designed to ensure neatness and a cohesive look, while buzz cuts provide a quick and manageable grooming option. Standard civilian haircuts can also be acceptable as long as they adhere to regulations and do not deviate into extremes that could detract from the Army's values and the individuals' adherence to the standards of appearance.