Can you use "cynicism" in the same way as "witticism"?
Solution 1:
"Witticism" is a fossilized play on words that comes from John Dryden--a portmanteau of "wit" and "criticism." So "criticism" is the relevant comparison.
"Criticism" can be either a count noun or a mass noun, but "witticism" seems to have been born and remained a count noun.
Then, "witticism" is and can be a count noun just because "criticism" can be a count noun, and it seems "criticism" is a count noun (in normal usage) just in being a nominalization of the verb "criticize." That is, in normal usage it counts singular instances of criticizing. On the other hand, "cynicism" nominalizes a state or property. There's no grammatical problem with counting cynicisms, but it would be a heroically abstract pursuit. No doubt some or other continental theorist talks about "cynicisms" but normal people don't count them.
It seems like the two words just don't have anything in common besides the "-ism" suffix. Edit: "Cynicism" doesn't have an analogous verb form.