Having the faculty of reason; endued with reason; rational; as, a reasonable being.
Governed by reason; being under the influence of reason; thinking, speaking, or acting rationally, or according to the dictates of reason; agreeable to reason; just; rational; as, the measure must satisfy all reasonable men.
Not excessive or immoderate; within due limits; proper; as, a reasonable demand, amount, price.
All, too, will bear in mind this sacred principle, that though the will of the majority is in all cases to prevail, that will to be rightful must be reasonable; that the minority possess their equal rights, which equal law must protect, and to violate would be oppression. Thomas Jefferson
The happiness of your life depends upon the quality of your thoughts: therefore, guard accordingly, and take care that you entertain no notions unsuitable to virtue and reasonable nature. Marcus Aurelius
Jealousy is both reasonable and belongs to reasonable men, while envy is base and belongs to the base, for the one makes himself get good things by jealousy, while the other does not allow his neighbour to have them through envy. Aristotle