Word stresses in red: viparīta karaṇī.
viparīta + karaṇī
karaṇī making; instrument, means.
The dot under the ṇ marks only a small shift in pronunciation.
The bar over the ī means it is pronounced noticeably long.
In origin the word is the feminine present participle, ‘doing, making’, from the verb kṛ, to make or do — source also of namas-kara ‘homage-making’, and kriyā and karma, both ‘action’.
viparīta divides into vi+pari+i+ta (i + i = ī)
vi off, away: indicating change
pari around, completely
i the VERBAL CORE: go
(compare from Latin: ex-i-t, going out)
ta indicates completion, like -ed.
Literally: gone completely into another state;
used in various senses e.g. upside down or perverse.
In modern practice viparīta-karaṇī commonly refers to a shoulderstand-like position with the torso arched like a bridge pose. In labelled illustrations from the 19th century the names of inversions were variable and viparīta-karaṇī is used sometimes for shoulderstand and sometimes for headstand. Evidently being upside down was the key thing and how you achieved that was secondary.
In the older haṭha yogic texts (which are transmitted without illustrations), viparīta-karaṇī is included not in the āsana section but as a mudrā. Mudrā, literally something like a signet ring (which both seals and imposes its sign), here leans toward the ‘closing’ side of its meaning: like a plug that blocks the flow of something. Karaṇī is feminine to agree with mudrā, a feminine noun (while āsana is neuter).
The Gheraṇḍa Samhitā (‘The Collection of Gh.’, dating from maybe 1700) gives an account of the viparīta-karaṇī (section 3, verses 29-32) that depends on a tantric body scheme:
While the Moon lies at the palate, the Sun lies at the navel where it destroys the substance amṛta (‘the undying’, related to the ambrosia eaten by the Greek gods: both are literally the ‘non-mortal’). According to the haṭha yogic view, in normal life this amṛta seeps entropically downward from its reservoir in the head. But if you ‘put the Moon down and the Sun up’ you can destroy old age and death. However, says another text, this will require three hours of inversion a day: but in only six month goodbye to wrinkles and grey hair! (So much for ‘unworldly’.) Very sensibly it adds, just invert for a moment the first time you do it.
The practical instruction in the GS consists only of: ‘with clear focus put head and both hands on the ground and lifting the legs be stable.’ Sounds like a three-point headstand. The inversion or reversal they have in mind is not so much of the body itself but of these two key points of internal tantric astronomy. It’s the Moon-Sun switch to keep the amṛta in the head bathed in the delicious cool moonlight of the palate.
‘Totally preposterous’ but we could look at it as a metaphor or a model about arresting decay and subverting norms of ‘higher’ and ‘lower’ ways to be. We’re used to models diagrammed on a screen or whiteboard, but this model is a performance enacted inside the body’s sensory field — which when we turn it upside down certainly guarantees intense attention on the immediate experience.
Modern yoga has wheeled in a replacement set of explanations and benefits to announce for going upside down. This began in the 1920’s with the recently-discovered endocrine system—shifting focus from little planets in the body to little glands.