योगवासिष्ठः yogavāsiṣṭhaḥ - book-3, chapter-24, verse-26

लोकपालपुरोध्वान्तधूमधूम्रेऽभ्रमन्दिरे ।
सिद्धगन्धर्वमिथुनप्रारब्धसुरतोत्सवम् ॥ २६ ॥

lokapālapurodhvāntadhūmadhūmre'bhramandire ,
siddhagandharvamithunaprārabdhasuratotsavam 26

26. lokapāla-pura-udhvānta-dhūma-dhūmre abramandire
siddha-gandharva-mithuna-prārabdha-surata-utsavam

26. lokapāla-pura-udhvānta-dhūma-dhūmre abramandire
siddha-gandharva-mithuna-prārabdha-surata-utsavam

26. In that cloud-palace, dark and smoky like the rising darkness and smoke from the cities of the world-guardians (lokapālas), a festival of lovemaking was initiated by pairs of perfected beings (siddhas) and gandharvas.

Words meanings summery:

• लोकपाल-पुर-उध्वान्त-धूम-धूम्रे (lokapāla-pura-udhvānta-dhūma-dhūmre) - in the place which is dark and smoky like the rising darkness/smoke from the cities of the world-guardians (lokapālas) (in the smoke-darkened darkness of the cities of the guardians of the world)

• अब्रमन्दिरे (abramandire) - in the cloud-palace, in the cloud-abode

• सिद्ध-गन्धर्व-मिथुन-प्रारब्ध-सुरत-उत्सवम् (siddha-gandharva-mithuna-prārabdha-surata-utsavam) - a festival of lovemaking commenced by pairs of perfected beings and gandharvas

Words meanings and morphology

लोकपाल-पुर-उध्वान्त-धूम-धूम्रे (lokapāla-pura-udhvānta-dhūma-dhūmre) - in the place which is dark and smoky like the rising darkness/smoke from the cities of the world-guardians (lokapālas) (in the smoke-darkened darkness of the cities of the guardians of the world)

(adjective)

Locative, neuter, singular of lokapāla-pura-udhvānta-dhūma-dhūmra

lokapāla-pura-udhvānta-dhūma-dhūmra - dark-grey like the rising smoke/darkness from the cities of the world-guardians (lokapālas)

Compound describing the nature of 'abramandira'

Compound type : Tatpurusha (within a larger Tatpurusha compound) (lokapāla+pura+udhvānta+dhūma+dhūmra)

• lokapāla – guardian of the world (lokapāla)
  noun (masculine)
  Compound: loka (world) + pāla (guardian)
• pura – city, town
  noun (neuter)
• udhvānta – rising darkness; rising smoke/dust
  adjective/noun (neuter)
  Past Passive Participle (from dhvan, to sound, often meaning 'darkness')
  From root √dhvan (to sound) with prefix ud-, implying 'spread' or 'rising', or can be taken as 'darkness' directly.
  Prefix: ud
  Root: dhvan (class 1)
• dhūma – smoke
  noun (masculine)
• dhūmra – smoky, smoke-colored, dark-grey
  adjective (masculine)
  Derived from dhūma (smoke)

Note: Qualifies 'abramandire'.

अब्रमन्दिरे (abramandire) - in the cloud-palace, in the cloud-abode

(noun)

Locative, neuter, singular of abramandira

abramandira - cloud-palace, cloud-abode

Tatpurusha compound: abra (cloud) + mandira (palace/abode)

Compound type : Tatpurusha (abra+mandira)

• abra – cloud
  noun (neuter)
• mandira – palace, temple, abode, dwelling
  noun (neuter)

Note: Main location being described.

सिद्ध-गन्धर्व-मिथुन-प्रारब्ध-सुरत-उत्सवम् (siddha-gandharva-mithuna-prārabdha-surata-utsavam) - a festival of lovemaking commenced by pairs of perfected beings and gandharvas

(noun)

masculine, singular of siddha-gandharva-mithuna-prārabdha-surata-utsava

siddha-gandharva-mithuna-prārabdha-surata-utsava - a festival of lovemaking commenced by pairs of perfected beings (siddhas) and gandharvas

Compound describing the nature/activity of the abode. 'Utsava' is the head noun.

Compound type : Tatpurusha (siddha-gandharva-mithuna+prārabdha+surata+utsava)

• siddha-gandharva-mithuna – pairs of perfected beings (siddhas) and gandharvas
  noun (neuter)
  Dvanda compound of siddha (perfected being) and gandharva (celestial musician) followed by mithuna (pair).
• prārabdha – commenced, begun, undertaken
  adjective (neuter)
  Past Passive Participle
  From root √rabh (to begin) with prefix pra-
  Prefix: pra
  Root: rabh (class 1)
• surata – sexual pleasure, copulation, lovemaking
  noun (neuter)
• utsava – festival, celebration, joy
  noun (masculine)

Note: This describes an attribute or event of the 'abramandira'. It functions as a predicate nominative describing what the place was, or an accusative if describing what was observed there.