Though the definition of rationality and the word rational are defined as states of reason, Rationality in its pure essense is a separate element from reason. Rationality and Reasonability are completely separate functions of the mind which produce together a definition of an action. A rational action is completely devoid of external awareness and is a result of pure desire from the conscious or unconscious mind. If you desire a large house, there is no reasonable explanation for such a desire, though it is completely rational. Your reasoning for you desire stems to create an outward mask to persuade yourself and others for such a desire.
A rational person, or Rational Actor, is a person who has desires for what they want and create strategies for obtaining those desires. Every person is a rational actor whether they know it or not. All actions, such as injustice and discrimination, are rational if they are used to allow the discriminator the ability to gain what they want. The main goal of a rational actor is to achieve or gain as many of their goals as possible, with the least amount of effort. Society would crumble into dust if all people where only rational.
Therefore, we must check rationality with the idea of Reasonability. Reason is not a natural human trait but evolved to aid the survival of humanity as it became a social creature. A reasonable person understands the limits of their own ability to gain their desires and begin to create systems of social cooperation, upon which equality(not always complete) and fair understanding supercede rational discriminatory policies of rational acting. Reason is a form of justification for acts which are rational but unfair to the vast majority of the populous]. However, reason is also the basic idea behind creating a free and equal society. Actions deemed reasonable by the vast majority of a populus are considered just by that populous.