Some quotes from Bhikkhu Katukurunde Ñāṇananda’s nibbāna sermons may be of relevance here:
From Nibbāna Sermon 1:
We have to make a similar comment on the meaning of the word Nibbāna. Here too one can see some unusual semantic developments in the commentarial period. It is very common these days to explain the etymology of the word Nibbāna with the help of a phrase like: Vānasaṅkhātāya taṇhāya nikkhantattā. And that is to say that Nibbāna is so called because it is an exit from craving which is a form of weaving.
To take the element vāna in the word to mean a form of weaving is as good as taking nāma in nāma-rūpa as some kind of bending. It is said that craving is a kind of weaving in the sense that it connects up one form of existence with another and the prefix ni is said to signify the exit from that weaving.
But nowhere in the suttas do we get this sort of etymology and interpretation. On the other hand it is obvious that the suttas use the word Nibbāna in the sense of ‘extinguishing’ or ‘extinction’. In fact this is the sense that brings out the true essence of the Dhamma.
For instance the Ratanasutta, which is so often chanted as a paritta, says that the Arahants go out like a lamp: Nibbanti dhīrā yathāyaṃ padīpo. "Those wise ones get extinguished even like this lamp."
The simile of a lamp getting extinguished is also found in the Dhātuvibhaṅgasutta of the Majjhima Nikāya. Sometimes it is the figure of a torch going out: Pajjotass’eva nibbānaṃ, vimokho cetaso ahu, “the mind’s release was like the extinguishing of a torch.”
The simile of the extinction of a fire is very often brought in as an illustration of Nibbāna and in the Aggivacchagottasutta of the Majjhima Nikāya we find the Buddha presenting it as a sustained simile, giving it a deeper philosophical dimension. Now when a fire burns, it does so with the help of firewood. When a fire is burning, if someone were to ask us: “What is burning?” - what shall we say as a reply? Is it the wood that is burning or the fire that is burning? The truth of the matter is that the wood burns because of the fire and the fire burns because of the wood. So it seems we already have here a case of relatedness of this to that, idappaccayatā. This itself shows that there is a very deep significance in the fire simile.
Nibbāna as a term for the ultimate aim of this Dhamma is equally significant because of its allusion to the going out of a fire. In the Asaṅkhatasaṃyutta of the Saṃyutta Nikāya as many as thirty-three terms are listed to denote this ultimate aim. But out of all these epithets, Nibbāna became the most widely used, probably because of its significant allusion to the fire. The fire simile holds the answer to many questions relating to the ultimate goal.
The wandering ascetic Vacchagotta, as well as many others, accused the Buddha of teaching a doctrine of annihilation: Sato sattassa ucchedaṃ vināsaṃ vibhavaṃ paññāpeti. Their accusation was that the Buddha proclaims the annihilation, destruction and non-existence of a being that is existent. And the Buddha answered them fairly and squarely with the fire simile.
“Now if a fire is burning in front of you dependent on grass and twigs as fuel, you would know that it is burning dependently and not independently, that there is no fire in the abstract. And when the fire goes out, with the exhaustion of that fuel, you would know that it has gone out because the conditions for its existence are no more.”
As a sidelight to the depth of this argument it may be mentioned that the Pāli word upādāna used in such contexts has the sense of both ‘fuel’ as well as ‘grasping’, and in fact, fuel is something that the fire grasps for its burning. Upādānapaccayā bhavo, “dependent on grasping is existence”. These are two very important links in the doctrine of dependent arising, paṭicca samuppāda.
The eternalists, overcome by the craving for existence, thought that there is some permanent essence in existence as a reality. But what had the Buddha to say about existence? He said that what is true for the fire is true for existence as well. That is to say that existence is dependent on grasping. So long as there is a grasping, there is an existence. As we saw above, the firewood is called upādāna because it catches fire. The fire catches hold of the wood, and the wood catches hold of the fire. And so we call it firewood. This is a case of a relation of this to that, idappaccayatā. Now it is the same with what is called ‘existence’, which is not an absolute reality.
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It seems that the deeper connotations of the word Nibbāna in the context of paṭicca samuppāda were not fully appreciated by the commentators. And that is why they went in search of a new etymology. They were too shy of the implications of the word ‘extinction’. Probably to avoid the charge of nihilism they felt compelled to reinterpret certain key passages on Nibbāna. They conceived Nibbāna as something existing out there in its own right. They would not say where, but sometimes they would even say that it is everywhere. With an undue grammatical emphasis they would say that it is on coming to that Nibbāna that lust and other defilements are abandoned: Nibbānaṃ āgamma rāgādayo khīṇāti ekameva nibbānaṃ rāgakkhayo dosakkhayo mohakkhayo ti vuccati.
But what do we find in the joyous utterances of the theras and therīs who had realized Nibbāna? As recorded in such texts as Thera- and Therī-gāthā they would say: Sītibhūto’smi nibbuto, “I am grown cool, extinguished as I am.” The words sītibhūta and nibbuta had a cooling effect even to the listener, though later scholars found them inadequate.
Extinction is something that occurs within an individual and it brings with it a unique bliss of appeasement. As the Ratanasutta says: Laddhā mudhā nibbutiṃ bhuñjamānā, “they experience the bliss of appeasement won free of charge.” Normally, appeasement is won at a cost, but here we have an appeasement that comes gratis.
From the worldly point of view ‘extinction’ means annihilation. It has connotations of a precipice that is much dreaded.