A critical atheist is defined as one who asserts that theism or belief in gods is irrational and should be rejected by all. The definition of critical atheist means that one has engaged in a critical evaluation of theistic claims and arguments then explicitly rejects them. A critical atheist is thus one who has engaged in critical deliberation over theism.
George H. Smith coined the term critical atheist and while it is sometimes used as a synonym for strong atheist, it is actually a type of explicit atheist that differs from strong atheist. There is, however, some overlap with positive atheist.
"The abolition of religion as the illusory happiness of the people is the demand for their real happiness. To call on them to give up their illusions about their condition is to call on them to give up a condition that requires illusions. The criticism of religion is, therefore, in embryo, the criticism of that vale of tears of which religion is the halo. Criticism has plucked the imaginary flowers on the chain not in order that man shall continue to bear that chain without fantasy or consolation, but so that he shall throw off the chain and pluck the living flower."
- Karl Marx, A Contribution to the Critique of Hegel's Philosophy of Right

