Irreligion

Irreligion (adjective form: nonreligious or irreligious) is the absence of religion, an indifference towards religion, a rejection of religion, or hostility towards religion. When characterized as the rejection of religious belief, it includes atheism and secular humanism. When characterized as hostility towards religion, it includes antitheism, anticlericalism and antireligion. When characterized as indifference to religion, it includes apatheism. When characterized as the absence of religious belief, it may also include agnosticism, ignosticism, nontheism, religious skepticism, and freethought. Irreligion may even include forms of theism depending on the religious context it is defined against, as in 18th century Europe where the epitome of irreligion was deism.

It has been estimated that 16% of the world population (1.1 billion people) are "non-religious" including agnostic, atheist, secular humanist, and people who answer "none" or "no religious preference" when asked an open-ended question about what is their religious preference. According to one source, it has been estimated that 40–50% of non-religious people hold belief in one or more deities, or in some higher power. Some evidence suggests that the fastest-growing religious status in the United States is "no religion", comprising nearly 20% of the adult public as of 2012. Those who lack a religious affiliation are sometimes referred to as "nones".