Red is a warm color within the auric spectrum. It corresponds to the element of fire and to the Root Chakra.
Keywords to describe a red aura person would be: passionate, loyal, competitive, loving, aggressive, strong, versatile, powerful, stressful, physical, sexual.
A more in-depth analysis of what a red aura means can be found in my previous entry here. Many shades of this color are listed, so you can find your specific shade meaning easily. :)