Thisness is a nonce word formed by adding the suffix -ness to the pronoun this. Normally pronouns can't take suffixes, which is why thisness is not really a formally accepted word. The meaning is clear enough, though, which is why the New Yorker was willing to use it in a quote.
If you're looking for a formally accepted alternative, you could use quiddity or haecceity. These words have the opposite problem of thisness: hardly anybody knows these words or understands what they mean, but they are nonetheless words which you can find in the dictionary.
I was intrigued by the "adjective ladder" data in a writeup by Hicks et al. cited by a linked answer to a related question in the comments, but I wanted to see it as a graph with error bars to help me gauge similarity and variance. I've plotted it below.
I recommend choosing just a handful of these key terms from this chart whose error bars are well separated from each other with somewhat similar distance between them. Perhaps:
- Awful (1.9 ± 0.08)
- Limited (3.8 ± 0.09, abysmal + 1.9)
- Fair (5.4 ± 0.08, limited + 1.6)
- Good (6.9 ± 0.10, fair + 1.5)
- Incredible (9.0 ± 0.8, good + 2.1)
The study has its own similar list of eleven items (abysmal, awful, bad, poor, mediocre, fair, good, great, excellent, amazing, phenomenal). Choosing a subset of six of those would simply entail taking every other: abysmal, bad, mediocre, good, excellent, phenomenal). For five, remove either abysmal or phenomenal.
Be careful not to pick terms that are too obscure! "Abysmal" and "Middling" just aren't popular words. (Though note that popularity is not the same as familiarity.) Consider checking Google Ngrams. Here are the most obscure words out of the 24 on the list (since WWII):
Fewest occurrences in printed books (via Google Ngrams):
Further research needed!
This paper had good methodology, randomizing the list, asking subjects to sort it, then rate it, and a few other tasks the helped them determine subjects' familiarity with each term. They found that "middling" was left blank by most participants, presumably due to a lack of familiarity.
When choosing words, try to avoid the less popular ones (like "middling"). I'd like to see "dismal," "average," and "heroic" in there as well, but keep the list from growing too large.
A larger version of this study could be broken down by region and educational level. If using something like Amazon Mechanical Turk, I suggest restricting participants to regions where English is the primary language rather than the lingua franca.
Best Answer
(Deceptively) profound -- not obviously, but deceptively profound. It sounds simple but has layers of complex meaning.
Source: dictionary definition at google search
Also read: ['deceptively' usage -- an earlier question and answers here at English.StackExchange.com] How should "deceptively" actually be used?
Other examples: google search results for the exact phrase "deceptively profound"
Option 2: understated wisdom.