Warrior classes in tribal culture
In tribal societies engaging in endemic warfare, warriors often form a caste or class of their own. In feudalism, the vassals essentially form a military or warrior class, even if in actual warfare, peasants may be called to fight as well. In some societies, warfare may be so central that the entire people (or, more often, large parts of the male population) may be considered warriors, for example in the Iron Age Germanic tribes and Indian clans like the Rajputs and Sikhs.
Women as warriors
While the warrior class in tribal societies is typically all-male, there are some exceptions on record where women (typically unmarried, young women) formed part of the warrior class.
A purported group of fighting women is the legendary Amazons, recorded in Classical Greek mythology.
Military castes in feudal society
The military caste in a feudal society is evolved from—but not identical with—the warrior class in a tribal society.
Many pre-modern states had castes, estates or social groups dedicated to warfare. This includes the Khalsa and Kshatriya castes in ancient and modern India, the samurai class in feudal Japan, and noble knights in feudal Europe.
In many societies in which a specialized warrior class exists, specific codes of conduct (ethical code or honour code) are established to ensure that the warrior class is not corrupted or otherwise dangerous to the rest of society. Common features include valuing honour in the forms of faith, loyalty and courage.
Examples include the following:
- Ethical codes of the early Germanic Peoples, as well as Prussian virtues
- Behavioral codes of discipline in the Spartan army.
- Virtues and skills of Gaelic kerns (see Gaels), modeled on the Fianna, semi-independent warrior bands in Irish mythology and Scottish mythology
- Medieval knights' code of chivalry;
- Samoa's Toa class, which used a warrior code known as fa'aaloalo (Respect) that is still in existence today;
- Kshatriya code of Dharma in India;
- Khalsa code of saint Soldiers in Sikhism;
- Japan's samurai class, which uses a warrior code known as Bushido (The Way Of The Warrior)
- Xiá in China;
- French Foreign Legion Code d'Honneur, still in use today;
- Spanish Legion Credo legionario, still in use today, and
- Arab-Persian ethical code of Furusiyya during the Middle ages
With the end of the Middle Ages and the professional standing armies of Early Modern warfare, the concept of a "warrior class" or "military caste" became an anachronism. The term "warrior" is still sometimes used, anachronistically, to refer to professional soldiers or mercenaries.
Due to the heroic connotations of the term "warrior", this metaphor is especially popular in publications advocating or recruiting for a country's military.
In addition to the literal meaning, now mostly historical, the term has acquired a figurative sense referring to "a person who shows or has shown great vigor, courage, or aggressiveness, as in politics or athletics." The "warrior" metaphor in sports is particularly popular in combat sport, as evident from brand names such as Warrior-1 MMA, Cage Warriors, Supreme Warrior Championship, etc. The company Warrior Roots combines the martial arts metaphor with the connotation of antiquity and tribal heritage by offering to test clients' "ancient ancestral roots" (i.e. their Y-Chromosome DNA) as well as their "genetic tendencies for various athletic characteristics".
A spiritual warrior is a person who battles with the "universal enemy," self-ignorance (avidya), the ultimate source of suffering according to dharmic philosophies. The term is applied in religious and metaphysical writing. There are self-described spiritual warriors. The spiritual warrior can be described as an archetype character on a journey for self discovery. 
- e.g. Wong, Leonard, "Leave No Man Behind: Recovering America’s Fallen Warriors." Armed Forces & Society, July 2005; vol. 31: pp. 599-622. Sagepub.com Watson, Bradley C.S., "The Western Ethical Tradition and the Morality of the Warrior." Armed Forces & Society, October 1999; vol. 26: pp. 55-72.Sagepub.com Samet, Elizabeth D., "Leaving No Warriors Behind: The Ancient Roots of a Modern Sensibility." Armed Forces & Society, July 2005; vol. 31: pp. 623-649.Sagepub.com Miller, Laura L. and Charles Moskos, "Humanitarians or Warriors?: Race, Gender, and Combat Status in Operations Restore Hope." Armed Forces & Society, July 1995; vol. 21: pp. 615-637. Sagepub.com
- Warrior, Random House Dictionary
- Grant, Kara-Leah (2009), "How yoga has the power to transform and release avidya (self-ignorance)", The Yoga Lunch Box, October 13, 2009 
- Oddo, Richard J ('A spiritual warrior') (1990), "Sharing of The Heart", Self-Published, 1989, ISBN 0-945637-02-0 [Amazon-US | Amazon-UK]
- Murdock, Maureen (1990), "The Heroine's Journey", Shambhala, June 23, 1990, p11, ISBN 0-87773-485-2 [Amazon-US | Amazon-UK]
- Ayvazyan A. "The Code of Honor of the Armenian Military (4-5th centuries)" (2000).
- Shannon E. French, Code of the Warrior - Exploring Warrior Values Past and Present (2003).
- Marion F. Sturkey "Warrior Culture of the U.S. Marines" (2001)
- Business Warrior