Life: b. 1944
"Atheist" is quite clear in its meaning of "somebody without a belief in God." It is more complex in its usage since it has often been used to blacken anyone with the slightest doubt about the teachings of religion.
source: Jim Herrick (1985). “Against the Faith: Essays on Deists, Skeptics, and Atheists”
topic: Atheist, Teaching, Doubt