Hindu philosophy is premised on the idea of God, not on a belief in God. Thus, the divine force, howsoever it may be perceived, or even if it is disregarded, is ever-present. Hinduism does not demand faith in God. Rather it provides links to the idea of God. Those interested can click on a link at any time.
What then describes Hindus if not faith in God, or acceptance of the tenets of Hinduism, or following the dictates of Hindu scriptures, or performing specific rituals? Responses often given to the question “Who is a Hindu?” include: followers of Hindu traditions, believers in Vedic philosophy, persons who follow dharma (a complex inclusive terms representing maintaining balance, staying on the path of truth, and fulfillment of duty), persons of righteousness, persons who will perform Hindu sacraments, persons who live a Hindu lifestyle, persons who uphold Hindu values, seekers of God, and persons who profess themselves to be Hindu.
The above replies are all correct, but none is definitive, given the wide diversity in individual beliefs. The last statement is probably the closest to the best answer. Nobody can judge the belief of a particular Hindu, but persons who believe themselves to be a Hindu know what they believe. Thus, a Hindu may be best described as someone who calls himself Hindu and who does not adhere to any other religion.