महाभारतः mahābhārataḥ - book-1, chapter-16, verse-18

बभूवात्र महाघोषो महामेघरवोपमः ।
उदधेर्मथ्यमानस्य मन्दरेण सुरासुरैः ॥१८॥

18. babhūvātra mahāghoṣo mahāmegharavopamaḥ ,
udadhermathyamānasya mandareṇa surāsuraiḥ.

18. babhūva atra mahāghoṣaḥ mahāmegharavopamaḥ
udadheḥ mathyamānasya mandareṇa surāsuraiḥ

18. Here, there arose a great roar, resembling the sound of massive thunderclouds, as the ocean was being churned by Mount Mandara and by the gods and asuras.

Words meanings summery:

• बभूव (babhūva) - there arose, there was (there was, it occurred, he/she/it became)

• अत्र (atra) - here (in this context/place) (here, in this place, thereupon)

• महाघोषः (mahāghoṣaḥ) - a great roar (a great sound, a loud roar)

• महामेघरवोपमः (mahāmegharavopamaḥ) - resembling the sound of massive thunderclouds (resembling the roar of great clouds)

• उदधेः (udadheḥ) - of the ocean (of the ocean, of the sea)

• मथ्यमानस्य (mathyamānasya) - of the ocean being churned (of that being churned)

• मन्दरेण (mandareṇa) - by Mount Mandara (by Mandara (name of a mountain))

• सुरासुरैः (surāsuraiḥ) - by the gods and asuras (by gods and asuras)

Words meanings and morphology

बभूव (babhūva) - there arose, there was (there was, it occurred, he/she/it became)

(verb)

3rd person , singular, active, past perfect (liṭ) of bhū

root bhū, perfect tense (liṭ)

Root: bhū (class 1)

अत्र (atra) - here (in this context/place) (here, in this place, thereupon)

(indeclinable)

adverb from idam (this) + -tra suffix

महाघोषः (mahāghoṣaḥ) - a great roar (a great sound, a loud roar)

(noun)

Nominative, masculine, singular of mahāghoṣa

mahāghoṣa - great sound, loud noise, roar

mahā (great) + ghoṣa (sound, roar)

Compound type : karmadhāraya (mahā+ghoṣa)

• mahā – great, large, mighty
  adjective
• ghoṣa – sound, noise, roar, cry
  noun (masculine)
  action noun
  from root ghuṣ (to sound)
  Root: ghuṣ (class 1)

महामेघरवोपमः (mahāmegharavopamaḥ) - resembling the sound of massive thunderclouds (resembling the roar of great clouds)

(adjective)

Nominative, masculine, singular of mahāmegharavopama

mahāmegharavopama - comparable to the sound of great clouds

mahā (great) + megha (cloud) + rava (sound) + upama (resembling)

Compound type : bahuvrīhi (mahā+megha+rava+upama)

• mahā – great, large, mighty
  adjective
• megha – cloud
  noun (masculine)
  from root mih (to sprinkle)
  Root: mih (class 1)
• rava – sound, roar, cry
  noun (masculine)
  action noun
  from root ru (to roar, cry)
  Root: ru (class 2)
• upama – resembling, similar, comparable
  adjective (masculine)

उदधेः (udadheḥ) - of the ocean (of the ocean, of the sea)

(noun)

Genitive, masculine, singular of udadhi

udadhi - ocean, sea, reservoir of water

ud (up) + dhā (to hold) -> udadhi (holder of waters)

Compound type : tatpuruṣa (uda+dhi)

• uda – water
  noun (neuter)
• dhi – container, receptacle, holding
  noun (masculine)
  action noun
  from root dhā (to place, hold)
  Root: dhā (class 3)

मथ्यमानस्य (mathyamānasya) - of the ocean being churned (of that being churned)

(participle)

Genitive, masculine, singular of mathyamāna

mathyamāna - being churned, being agitated

present participle

from root math (to churn), passive voice (-yamāna)

Root: math (class 1)

मन्दरेण (mandareṇa) - by Mount Mandara (by Mandara (name of a mountain))

(noun)

Instrumental, masculine, singular of mandara

mandara - Mandara (name of a mythical mountain used as a churning rod)

सुरासुरैः (surāsuraiḥ) - by the gods and asuras (by gods and asuras)

(noun)

Instrumental, masculine, plural of surāsura

surāsura - gods and demons

sura (god) + asura (demon)

Compound type : dvandva (sura+asura)

• sura – god, deity
  noun (masculine)
• asura – demon, evil spirit
  noun (masculine)
  a- (not) + sura (god)