Because comments were turned off on "Root haughtiness", reader JCL added this comment to a different post:
I just wanted to propose that the unwritten restrictions on the use of -ass has NOTHING to do with the meaning of the adjective, and everything to do with meter. One-syllable words (/), trochees (/ -), and dactyls (/ - -) work, but everything else doesn't. For example: smart-ass, purple-ass, raggedy-ass.
Try it with words that aren't monosyllabic, trochees, or dactyls. Doesn't seem right, does it? Again, has nothing to do with the meaning of the words. What do you think of this hypothesis?
A piece of advice: don't do this. As our Comments Policy explains,
Note that comments will be enabled on some posts, and not on others. If comments are not enabled on a particular post, please don't use the comments on a different post to discuss it. If you have something to say about a post where comments are not enabled, you can email the author (we are all professional scholars with easy-to-discover email addresses, though publishing them here would attract the attention of robots and bring us floods of spam).
So I deleted JCL's comment, and similar attempts in the future will get the same treatment.
In fact, I no longer think that publishing email addresses has much to do with spam density. But if you can't use web search to find an email address for Geoff Pullum or for me, or if you don't care to invest the 20 seconds that it would take you to do so, then your comment probably wasn't worth it.
As for the content of JCL's proposal, I'm not convinced. It's easy to find "words that aren't monosyllabic, trochees, or dactyls" that have convincing web counter-examples: references to "some short selective-ass memories", or complaints about "corrupt-ass refs" and "sorry dishonest-ass politicians". These seem entirely idiomatic to me.