योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-74, verse-15

अग्निलोकस्तथौर्वाग्निः पित्तमस्यातिदुःसहम् ।
वातस्कन्धमहावाताः प्राणापाना हृदि स्थिताः ॥ १५ ॥

agnilokastathaurvāgniḥ pittamasyātiduḥsaham ,
vātaskandhamahāvātāḥ prāṇāpānā hṛdi sthitāḥ 15

15. agnilokaḥ tathā aurvāgniḥ pittam asya ati-dussaham
vātaskandha-mahāvātāḥ prāṇāpānā hṛdi sthitāḥ

15. agnilokaḥ tathā aurvāgniḥ asya pittam ati-dussaham
vātaskandha-mahāvātāḥ prāṇāpānā hṛdi sthitāḥ

15. Similarly, the world of Agni (agniloka) is his submarine fire (aurvāgni), and his bile (pitta) is exceedingly fierce. The masses of wind and great winds are his prāṇa and apāna vital airs, located in his heart.

Words meanings summery:

• अग्निलोकः (agnilokaḥ) - world of fire (Agni)

• तथा (tathā) - thus, so, similarly, likewise

• और्वाग्निः (aurvāgniḥ) - submarine fire, gastric fire

• पित्तम् (pittam) - bile, one of the three bodily humors (doṣas)

• अस्य (asya) - his, its

• अति-दुस्सहम् (ati-dussaham) - very difficult to bear, unbearable, exceedingly fierce

• वातस्कन्ध-महावाताः (vātaskandha-mahāvātāḥ) - masses of wind and great winds; mighty hurricanes

• प्राणापाना (prāṇāpānā) - vital airs (prāṇa and apāna)

• हृदि (hṛdi) - in the heart, in the mind

• स्थिताः (sthitāḥ) - situated, located, standing

Words meanings and morphology

अग्निलोकः (agnilokaḥ) - world of fire (Agni)

(noun)

Nominative, masculine, singular of agniloka

agniloka - the world of Agni, the realm of fire

Compound type : Tatpurusha (agni+loka)

• agni – fire, god of fire
  noun (masculine)
• loka – world, realm, people, space
  noun (masculine)

तथा (tathā) - thus, so, similarly, likewise

(indeclinable)

और्वाग्निः (aurvāgniḥ) - submarine fire, gastric fire

(noun)

Nominative, masculine, singular of aurvāgni

aurvāgni - submarine fire, fire of the sage Urva, digestive/gastric fire

A compound of Urva (a sage associated with this fire) and Agni (fire).

Compound type : Tatpurusha (urva+agni)

• urva – name of a sage, great, terrible
  noun (masculine)
• agni – fire, god of fire
  noun (masculine)

पित्तम् (pittam) - bile, one of the three bodily humors (doṣas)

(noun)

Nominative, neuter, singular of pitta

pitta - bile, gall, one of the three bodily humors (doṣas) in Ayurveda, associated with fire and metabolism

अस्य (asya) - his, its

(pronoun)

Genitive, masculine, singular of idam

idam - this, he, she, it (as a pronoun)

Genitive singular form of the demonstrative pronoun idam.

अति-दुस्सहम् (ati-dussaham) - very difficult to bear, unbearable, exceedingly fierce

(adjective)

Nominative, neuter, singular of ati-dussaha

ati-dussaha - very difficult to bear, unbearable, intolerable, extremely formidable

Compound formed with the prefix ati- (very, exceedingly) and dussaha (difficult to bear).

Compound type : Pradi Tatpurusha (ati+dussaha)

• ati – beyond, over, excessively, very
  indeclinable
  Adverbial prefix.
• dussaha – difficult to bear, hard to endure, formidable
  adjective (neuter)
  Compound of dur (bad, difficult) and saha (bearing, enduring).
  Prefix: dus
  Root: sah (class 1)

वातस्कन्ध-महावाताः (vātaskandha-mahāvātāḥ) - masses of wind and great winds; mighty hurricanes

(noun)

Nominative, masculine, plural of vātaskandha-mahāvāta

vātaskandha-mahāvāta - masses of wind and great winds, powerful storm winds

Compound of vātaskandha (mass of wind) and mahāvāta (great wind).

Compound type : Dvandva (vātaskandha+mahāvāta)

• vātaskandha – mass of wind, whirlwind
  noun (masculine)
• mahāvāta – great wind, hurricane
  noun (masculine)

प्राणापाना (prāṇāpānā) - vital airs (prāṇa and apāna)

(noun)

Nominative, feminine, singular of prāṇāpāna

prāṇāpāna - the two vital airs, prāṇa (inward moving) and apāna (downward moving)

Dvandva compound of prāṇa and apāna.

Compound type : Dvandva (prāṇa+apāna)

• prāṇa – life breath, vital air, respiration (prāṇa)
  noun (masculine)
  Prefix: pra
• apāna – downward vital air, excretion (apāna)
  noun (masculine)
  Prefix: apa

Note: Grammatically, it should be prāṇāpānāḥ to agree with vātaskandha-mahāvātāḥ and sthitāḥ (masculine plural nominative).

हृदि (hṛdi) - in the heart, in the mind

(noun)

Locative, neuter, singular of hṛd

hṛd - heart, mind, breast, essence

Locative singular form of the noun hṛd (which can be neuter or feminine).

स्थिताः (sthitāḥ) - situated, located, standing

(adjective)

Nominative, masculine, plural of sthita

sthita - standing, placed, situated, existing, firm, steady

Past Passive Participle

Derived from the root sthā (to stand, stay), forming a past passive participle with the suffix -ta.

Root: sthā (class 1)

Note: Agrees with vātaskandha-mahāvātāḥ and prāṇāpānā (contextually plural masculine).