Abandonment of one's religious faith, a political party, one's principles, or a cause.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "apostasy" in a sentence
"The term apostasy is derived from Greek, meaning "political rebel", as applied to rebellion against God, its law and the faith of Israel."
"For instance, death for apostasy is universal in the major schools of Islam."
"From a personal perspective, I have judged the ACoC and TEC to be in apostasy and the ABC to be actively defending both TEC and ACoC."