The root meaning of fisq involves departing from obedience. According to context, the word may describe an unbeliever or a Muslim who commits serious disobedience. Therefore, every occurrence of “fāsiq” in revelation cannot be given one invariant theological meaning.
A verse explicitly contrasting faith with unbelief may employ the term differently from a verse describing conflict between groups still called believers. Context determines whether the discussion concerns unbelief itself or misconduct without automatic loss of faith.