* Abstract Characteristic: This refers to qualities that are not physical, such as personality traits, emotions, or intellectual abilities. For example, the opposite of "tall" could be "intelligent."
* Internal Characteristic: This refers to aspects of a person or thing that are not visible or tangible. For example, the opposite of "brown hair" could be "kindness."
* Non-physical Attribute: This is a broader term encompassing any characteristic that is not directly related to the physical body. For example, the opposite of "muscular" could be "creative."
Ultimately, the "opposite" of a physical characteristic depends on what aspect you are trying to contrast it with.