atheistical
/əˌθiːɪsˈtɪkəl/ or /æˌθiːɪsˈtɪkəl/Definitions
1. adjective
relating to or characterized by atheism; opposed to religious or spiritual beliefs
“The author’s atheistical views sparked a heated debate among critics.”
2. noun
a person who holds atheistical views or believes that there is no God
“The novelist was known for her atheistical character, who questioned the existence of a higher power.”