I hope readers of this blog, Muslims in particular, will attempt to understand secularism in a non-polemical manner. It isn't licentiousness (الإباحية), and it can be uncommitted on essential religious positions, so it is not equivalent to atheism.
Lindsay's layman definition of secularism is "the view that: government should not involve itself with religious matters; religious doctrine should play no role in shaping public policy or in the discourse about public policy; and religious institutions and beliefs should not enjoy a privileged position within society." [p. 18]