योगवासिष्ठः yogavāsiṣṭhaḥ - book-3, chapter-37, verse-8

अवन्तीस्यन्दनश्रेणीकुन्तिपाञ्चनदेरितैः ।
स्पन्दमाना विद्रवन्ती निपपात महाभृगौ ॥ ८ ॥

avantīsyandanaśreṇīkuntipāñcanaderitaiḥ ,
spandamānā vidravantī nipapāta mahābhṛgau 8

8. avantīsyandanaśreṇīkuntipāñcanaderitaiḥ
spandamānā vidravantī nipapāta mahābhṛgau

8. avantīsyandanaśreṇīkuntipāñcanaderitaiḥ
spandamānā vidravantī mahābhṛgau nipapāta

8. Driven by the Avantīs, the chariot formations, the Kuntis, and the Pañcanadas, (it), trembling and fleeing, fell down upon a great mountain.

Words meanings summery:

• अवन्तीस्यन्दनश्रेणीकुन्तिपाञ्चनदेरितैः (avantīsyandanaśreṇīkuntipāñcanaderitaiḥ) - By the forces driven by the Avantīs, the chariot formations, the Kuntis, and the Pañcanadas. (By those impelled by/from Avanti, chariot-lines, Kunti, and Pañcanada.)

• स्पन्दमाना (spandamānā) - trembling, vibrating, moving.

• विद्रवन्ती (vidravantī) - fleeing, running away.

• निपपात (nipapāta) - fell down.

• महाभृगौ (mahābhṛgau) - upon a great mountain. (on the great mountain/Bhṛgu.)

Words meanings and morphology

अवन्तीस्यन्दनश्रेणीकुन्तिपाञ्चनदेरितैः (avantīsyandanaśreṇīkuntipāñcanaderitaiḥ) - By the forces driven by the Avantīs, the chariot formations, the Kuntis, and the Pañcanadas. (By those impelled by/from Avanti, chariot-lines, Kunti, and Pañcanada.)

(adjective)

Instrumental, masculine, plural of avantīsyandanaśreṇīkuntipāñcanaderita

avantīsyandanaśreṇīkuntipāñcanaderita - impelled by Avanti, chariot-lines, Kunti, and Pañcanada

Compound type : tatpurusha (avantī+syandanaśreṇī+kunti+pāñcanada+īrita)

• avantī – name of a country; its people
  proper noun (feminine)
• syandanaśreṇī – line/multitude of chariots
  noun (feminine)
• kunti – name of a country; its people
  proper noun (feminine)
• pāñcanada – relating to the five rivers; the region of five rivers (e.g., Punjab); its people
  proper noun (masculine)
• īrita – moved, agitated, impelled
  verbal derivative
  Past Passive Participle
  From root √īr (to move, impel).
  Root: īr

स्पन्दमाना (spandamānā) - trembling, vibrating, moving.

(verbal derivative)

विद्रवन्ती (vidravantī) - fleeing, running away.

(verbal derivative)

निपपात (nipapāta) - fell down.

(verb)

3rd person , singular, active, perfect (liṭ) of pat

Perfect Tense (Liṭ Lakāra)

3rd person singular

Prefix: ni

Root: pat (class 1)

महाभृगौ (mahābhṛgau) - upon a great mountain. (on the great mountain/Bhṛgu.)

(noun)

Locative, masculine, singular of mahābhṛgu

mahābhṛgu - a great mountain; a specific mountain; a great sage of the Bhṛgu lineage

Compound type : karmadhāraya (mahā+bhṛgu)

• mahā – great, large, mighty
  adjective
• bhṛgu – name of a sage; a mountain
  noun (masculine)