Sometimes technical terms in the EBTs are used very frequently, but with little context. They occur in doctrinal passages, and the basic meaning is clear in context, yet pinning down the exact nuance can be difficult. In such cases we try to draw upon the meanings in everyday contexts, for that is how language works: from the simple and mundane to the abstract and philosophical.
One such term is the well-known nibbidā. Dictionaries give meanings such as “disgust”, “dissatisfaction”, “aversion”, “weariness”, “disenchantment”, “turning away”, “indifference”. That’s quite a semantic range for a term that almost always appears in exactly the same few doctrinal tropes! A few of these senses apply only to later texts, such as “weariness”.
Ven Bodhi followed Ven Nyanamoli in rendering as “disenchantment” for the Majjhima. In the Samyutta, he noted that it sometimes has a stronger sense, and used “revulsion”. While he gives no sources, I believe this was in response to a note from Ajahn Brahm, who has long argued for a stronger meaning. In Ven Bodhi’s Anguttara translation, however, he reverted to “disenchantment”, with (so far as I can see) no explanation.
I have looked, but I can’t find any cases that confirm the “stronger” sense of nibbidā. Perhaps they were thinking of contexts such as AN 9.15. This speaks of the body as a boil, with nine wounds oozing disgusting filth. The text finishes urging the monks to have nibbidā for the body. The problem is that there’s no real connection between the “disgustingness” of the body and the experience of nibbidā per se. After all, one is supposed to have nibbidā when seeing impermanence, or suffering, and so on. Nibbidā doesn’t mean disgust, it is the response when seeing something disgusting (or impermanent or whatever).
It is also worth noting that when the stock phrases that speak of things that are disgusting—such as aṭṭīyati harāyati jigucchati—are used, nibbidā is not found. The two ideas are distinct. Even places that relate the two ideas, such as the passage discussed above, are rare.
So what do we find in the everyday sense? By far the most common idiom is a phrase meaning to “leave disappointed” (nibbijja pakkamati). It’s used of the Buddha being disappointed in his former teachers (MN 26); the five monks being disappointed in the bodhisatta (MN 36); and the Jains being disappointed in the behavior of their monks after the passing of their teacher (DN 29). The same idiom is also used of a jackal who can’t get any meat out of a tortoise that’s all withdrawn in its shell; and Mara who gets disappointed when he can’t find a vulnerability (SN 35.240).
Mara also features in another couple of related idioms, including the “verses of disappointment” (nibbejanīyā gāthāyo) he recites when he realizes his failure to trap the Buddha (SN 4.24). Both he and his daughters appear in the context of “leaving disappointed”, which has the same sense as nibbijja pakkamati, but here we have nibbijjāpema (= nibbijja apema where apema = apa + eti).
All of these cases have basically the same meaning, to have your expectations or hopes dashed. “Disenchantment” isn’t quite right. Either “disillusionment” or “disappointment” would seem to mostly work okay. Note, though, that “disillusionment” means to have one’s unrealistic ideas corrected. But in some examples, specifically the case of the five monks leaving the Buddha, nibbidā doesn’t necessarily mean that one realizes the truth. In that case, they are experiencing nibbidā, but still based on their misunderstanding. Thus “disappointment” would fit better in such cases.
Clearly, in any case, there is no justification for the “stronger” renderings such as “disgust” or “revulsion”. You might argue that such sense could work in some cases: the five monks were disgusted with the bodhisatta when he started eating solid food. But it doesn’t fit the case of the Buddha leaving his former teachers, nor the jackal who can’t find food. “Disappointment” covers all these cases.
In doctrinal contexts, however, “disappointment” wouldn’t work. Practice Dhamma, and it leads to disappointment! In such cases, “disillusionment” works better.