Insufferable suffixes

A secular friend, attempting to get my goat, wrote:  “If I can call a Muslim an 'Islamist,' can I call a Christian a 'Christianist'?”

I replied, imperturbably: 

Absolutely;  I have myself explicitly argued for the validity of that term:

http://worldofdrjustice.blogspot.com/2011/10/dominionism.html
However, it is not synonymous with "Christian", any more than (in proper use) "Islamist" is synonymous with "Muslim".

That said, we must observe that the term Islamist, originally a coinage of careful scholars who are trained to know one word from another,  has, in leaking out into the popular media, quite likely lost all precision, and to the laity seems like just one more synonym of (as a noun) Moslem/Muslim/Musselman or (as an adjective) Muslim/Islamic.  As such -- since it is always used pejoratively -- it is mischief-working.

Yet -- that said -- it certainly is true that, in any technical field requiring an abundance of fine distinctions, the weak reeds of suffixes are sometimes impressed into service.   Thus, a répartition met-with just a moment ago, in Wikipedia:  a bounded lattice is

* Atomic if, for every nonzero element x of L, there exists an atom a of L such that a=< x;

* Atomistic if every element of L is a supremum of atoms.

Nun -- alles klar?

[Update]  For another example of differentiated doublets, cf. our comments on sophistical vs. sophisticated.