definition of apostate
apostasy. Use apostasy in a sentence. LINK / CITE ADD TO WORD LIST. noun. The definition of an apostasy is the act of leaving behind, or straying from, your religious or political beliefs or your principles.An example of apostasy is when someone decides to become atheist.postasy. Use apostasy in a sentence. LINK / CITE ADD TO WORD LIST. noun. The definition of an apostasy is the act of leaving behind, or straying from, your religious or political beliefs or your principles.