takfir no relation religious infidelity
Usage
The practice of declaring another Muslim as a kafir is takfir. Kufr (unbelief) and shirk (idolatry) are used throughout the Quran and sometimes used interchangeably by Muslims. According to Salafist scholars, Kufr is the "denial of the Truth" (truth in the form of articles of faith in Islam), and shirk means devoting "acts of worship to anything beside God" or "the worship of idols and other created beings". So a mushrik may worship other things while also "acknowledging God".
no relation