The disbelief or denial of the existence of a God, or supreme intelligent Being. [1913 Webster]
"Atheism is a ferocious system, that leaves nothing above us to excite awe, nor around us to awaken tenderness." [1913 Webster]

"Atheism and pantheism are often wrongly confounded." [1913 Webster]
Godlessness. [1913 Webster]

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OXFORD DICTIONARY

atheism, n. the theory or belief that God does not exist.

Derivative

atheist n. atheistic adj. atheistical adj.

Etymology

F ath{eacute}isme f. Gk atheos without God f. a- not + theos god

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THESAURUS

atheism

agnosticism, apostasy, backsliding, denial, desertion, disbelief, discredit, faithlessness, fall from grace, gentilism, heresy, impiety, impiousness, inability to believe, incredulity, infidelity, irreligion, irreverence, lapse, lapse from grace, minimifidianism, misbelief, nonbelief, nullifidianism, recidivism, recreancy, rejection, secularism, unbelief, unbelievingness, undutifulness

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ROGET THESAURUS

atheism

Heterodoxy

N heterodoxy, error, false doctrine, heresy, schism, schismaticism, schismaticalness, recusancy, backsliding, apostasy, atheism, bigotry, fanaticism, iconoclasm, hyperorthodoxy, precisianism, bibliolatry, sabbatarianism, puritanism, anthropomorphism, idolatry, superstition, dissent, sectarism, sectarianism, noncomformity, secularism, syncretism, protestantism, Arianism, Adventism, Jansenism, Stundism, Erastianism, Calvinism, quakerism, methodism, anabaptism, Puseyism, tractarianism, ritualism, Origenism, Sabellianism, Socinianism, Deism, Theism, materialism, positivism, latitudinarianism High Church, Low Church, Broad Church, Free Church, ultramontanism, papism, papistry, monkery, papacy, Anglicanism, Catholicism, Romanism, popery, Scarlet Lady, Church of Rome, Greek Church, paganism, heathenism, ethicism, mythology, polytheism, ditheism, tritheism, dualism, heathendom, Judaism, Gentilism, Islamism, Islam, Mohammedanism, Babism, Sufiism, Neoplatonism, Turcism, Brahminism, Hinduism, Buddhism, Sabianism, Gnosticism, Hylotheism, Mormonism, Christian Science, heretic, apostate, antichrist, pagan, heathen, painim, paynim, giaour, gentile, pantheist, polytheist, idolator, schismatic, sectary, sectarian, sectarist, seceder, separatist, recusant, dissenter, nonconformist, nonjuror, bigot, fanatic, abdal, iconoclast, latitudinarian, Deist, Theist, Unitarian, positivist, materialist, Homoiousian, Homoousian, limitarian, theosophist, ubiquitarian, skeptic, Protestant, Huguenot, orthodox dissenter, Congregationalist, Independent, Episcopalian, Presbyterian, Lutheran, Calvinist, Methodist, Wesleyan, Ana, Baptist, Mormon, Latter-day Saint, Irvingite, Sandemanian, Glassite, Erastian, Sublapsarian, Supralapsarian, Gentoo, Antinomian, Swedenborgian, Adventist, Bible Christian, Bryanite, Brownian, Christian Scientist, Dunker, Ebionite, Eusebian, Faith Curer, Curist, Familist, Jovinianist, Libadist, Quaker, Restitutionist, Shaker, Stundist, Tunker, ultramontane, Anglican, Oxford School, tractarian, Puseyite, ritualist, Puritan, Catholic, Roman, Catholic, Romanist, papist, Jew, Hebrew, Rabbinist, Rabbist, Sadducee, Babist, Motazilite, Mohammedan, Mussulman, Moslem, Shiah, Sunni, Wahabi, Osmanli, Brahmin, Brahman, Parsee, Sufi, Buddhist, Magi, Gymnosophist, fire worshiper, Sabian, Gnostic, Rosicrucian, heterodox, heretical, unorthodox, unscriptural, uncanonical, antiscriptural, apocryphal, unchristian, antichristian, schismatic, recusant, iconoclastic, sectarian, dissenting, dissident, secular, (lay), pagan, heathen, heathenish, ethnic, ethnical, gentile, paynim, pantheistic, polytheistic, Judaical, Mohammedan, Brahminical, Buddhist, Romish, Protestant, bigoted superstitious, fanatical, idolatrous, visionary, slave to no sect, superstitione tollenda religio non tollitur.

Irreligion

N irreligion, indevotion, godlessness, ungodliness, laxity, quietism, skepticism, doubt, unbelief, disbelief, incredulity, incredulousness, want of faith, want of belief, pyrrhonism, bout, agnosticism, atheism, deism, hylotheism, materialism, positivism, nihilism, infidelity, freethinking, antichristianity, rationalism, neology, atheist, skeptic, unbeliever, deist, infidel, pyrrhonist, giaour, heathen, alien, gentile, Nazarene, espri fort, freethinker, latitudinarian, rationalist, materialist, positivist, nihilist, agnostic, somatist, theophobist, irreligious, indevout, undevout, devoutless, godless, graceless, ungodly, unholy, unsanctified, unhallowed, atheistic, without God, skeptical, freethinking, unbelieving, unconverted, incredulous, faithless, lacking faith, deistical, unchristian, antichristian, worldly, mundane, earthly, carnal, worldly minded, irreligiously.

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