A keshdhari is a Sikh who keeps the hair uncut but has not received amrit, the word meaning one who bears the kesh, and the category exists because these two things do not always go together.
Form without initiation
The keshdhari maintains the most visible of the outward marks of the Sikh, the uncut hair kept covered by the turban, and generally observes much of the tradition, but has not taken the formal initiation into the Khalsa, so stands between full initiation and the looser adherence of those who keep no outward form. The category is needed precisely because keeping the uncut hair, which is the first of the five articles, and taking the initiation that binds one to all of them, are distinct acts, and many keep the former without having taken the latter.
A degree of adherence
The keshdhari thus represents an intermediate standing in the gradation the tradition recognises, below the fully initiated amritdhari and above the sahajdhari who keeps no outward form, and it reflects the reality that observance in a living community comes in degrees rather than in a single all-or-nothing state. Many Sikhs live as keshdhari for much or all of their lives, maintaining the visible identity and much of the practice without the formal step of initiation, which may be taken later or not at all. The category is descriptive of a real and common way of belonging to the Sikh community, and its existence shows the tradition acknowledging degrees of commitment rather than recognising only the fully initiated.