वाल्मीकि-रामायणम् vālmīki-rāmāyaṇam - book-4, chapter-66, verse-41

त्यज्यमानमहासानुः संनिलीनमहोरगः ।
शैलशृङ्गशिलोद्घातस्तदाभूत् स महागिरिः ॥४१॥

41. tyajyamānamahāsānuḥ saṃnilīnamahoragaḥ ,
śailaśṛṅgaśilodghātastadābhūt sa mahāgiriḥ.

41. tyajyamānamahāsānuḥ saṃnilīnamahoragaḥ
śailaśṛṅgaśilodghātaḥ tadā abhūt saḥ mahāgiriḥ

41. tadā saḥ mahāgiriḥ tyajyamānamahāsānuḥ
saṃnilīnamahoragaḥ śailaśṛṅgaśilodghātaḥ abhūt

41. Then that great mountain (mahāgiri) became one with its mighty ridges being deserted, its great serpents deeply concealed, and its mountain peaks shattered with falling rocks.

Words meanings summery:

• त्यज्यमानमहासानुः (tyajyamānamahāsānuḥ) - having its mighty ridges being abandoned/deserted

• संनिलीनमहोरगः (saṁnilīnamahoragaḥ) - having great serpents deeply concealed

• शैलशृङ्गशिलोद्घातः (śailaśṛṅgaśilodghātaḥ) - having mountain peaks with shattered rocks

• तदा (tadā) - then, at that time

• अभूत् (abhūt) - was, became

• सः (saḥ) - that, he, it

• महागिरिः (mahāgiriḥ) - great mountain

Words meanings and morphology

त्यज्यमानमहासानुः (tyajyamānamahāsānuḥ) - having its mighty ridges being abandoned/deserted

(adjective)

Nominative, masculine, singular of tyajyamānamahāsānu

tyajyamānamahāsānu - having mighty ridges being abandoned

Compound type : bahuvrīhi (tyajyamāna+mahāsānu)

• tyajyamāna – being abandoned, being left
  adjective
  Present Passive Participle
  Derived from √tyaj (to abandon), formed with the suffix -yamāna.
  Root: tyaj (class 1)
• mahāsānu – great peak, mighty ridge
  noun (masculine)

Note: Refers to the great mountain.

संनिलीनमहोरगः (saṁnilīnamahoragaḥ) - having great serpents deeply concealed

(adjective)

Nominative, masculine, singular of saṃnilīnamahoraga

saṁnilīnamahoraga - having great serpents deeply hidden/recessed

Compound type : bahuvrīhi (saṃnilīna+mahoraga)

• saṃnilīna – deeply hidden, concealed, merged
  adjective
  Past Passive Participle
  Derived from saṃ-ni-√lī (to cling, hide, dissolve).
  Prefixes: sam+ni
  Root: lī (class 4)
• mahoraga – great serpent, large snake
  noun (masculine)

Note: Refers to the great mountain.

शैलशृङ्गशिलोद्घातः (śailaśṛṅgaśilodghātaḥ) - having mountain peaks with shattered rocks

(adjective)

Nominative, masculine, singular of śailaśṛṅgaśilodghāta

śailaśṛṅgaśilodghāta - having mountain peaks with rock shattering/breaking

Compound type : bahuvrīhi (śailaśṛṅga+śilodghāta)

• śailaśṛṅga – mountain peak
  noun (neuter)
• śilodghāta – shattering of rocks, falling rocks
  noun (masculine)
  Prefix: ut
  Root: han (class 2)

Note: Refers to the great mountain.

तदा (tadā) - then, at that time

(indeclinable)

अभूत् (abhūt) - was, became

(verb)

3rd person , singular, active, aorist (luṅ) of bhū

Aorist Active

Root verb bhū, 1st conjugation, aorist tense, 3rd person singular, active voice.

Root: bhū (class 1)

सः (saḥ) - that, he, it

(pronoun)

Nominative, masculine, singular of tad

tad - that, he, she, it

Note: Refers to the great mountain.

महागिरिः (mahāgiriḥ) - great mountain

(noun)

Nominative, masculine, singular of mahāgiri

mahāgiri - great mountain

Compound type : karmadhāraya (mahā+giri)

• mahā – great, large, mighty
  adjective
• giri – mountain, hill
  noun (masculine)

Note: The main subject noun of the sentence.