One who disagrees or dissents; one who separates from the established religion.
Sometimes Dissident: in the kingdom of Poland, the name for Christians not part of the Roman Catholic Church.
A person who formally opposes the current political structure, the political group in power, the policies of the political group in power, or current laws.
In a manner that disagrees; dissenting; discordant.
A disbeliever, a denier: someone who rejects or disbelieves in God as per Islam (Arabic: الله Allāh) or the tenets of Islam; or more broadly any non-Muslim.