योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-64, verse-29

क्वचिदत्यन्तनिःशून्यः क्वचिज्जनपदावृतः ।
क्वचिच्छ्वभ्रान्तगम्भीरः क्वचित्पातालभीषणः ॥ २९ ॥

kvacidatyantaniḥśūnyaḥ kvacijjanapadāvṛtaḥ ,
kvacicchvabhrāntagambhīraḥ kvacitpātālabhīṣaṇaḥ 29

29. kvacit atyantaniḥśūnyaḥ kvacit janapadāvṛtaḥ
kvacit śvabhrāntagambhīraḥ kvacit pātālabhīṣaṇaḥ

29. kvacit atyantaniḥśūnyaḥ kvacit janapadāvṛtaḥ
kvacit śvabhrāntagambhīraḥ kvacit pātālabhīṣaṇaḥ

29. Sometimes it is utterly desolate, and at other times, it is surrounded by populated areas. Sometimes it is profoundly deep like an abyss, and at other times, terrifying like the netherworld.

Words meanings summery:

• क्वचित् (kvacit) - sometimes, somewhere, in some place

• अत्यन्तनिःशून्यः (atyantaniḥśūnyaḥ) - exceedingly desolate, extremely empty

• क्वचित् (kvacit) - sometimes, somewhere, in some place

• जनपदावृतः (janapadāvṛtaḥ) - surrounded by populated areas, covered with inhabited lands

• क्वचित् (kvacit) - sometimes, somewhere, in some place

• श्वभ्रान्तगम्भीरः (śvabhrāntagambhīraḥ) - profoundly deep due to chasms, deep with chasms within

• क्वचित् (kvacit) - sometimes, somewhere, in some place

• पातालभीषणः (pātālabhīṣaṇaḥ) - terrifying like the netherworld, dreadful like Pātāla

Words meanings and morphology

क्वचित् (kvacit) - sometimes, somewhere, in some place

(indeclinable)

अत्यन्तनिःशून्यः (atyantaniḥśūnyaḥ) - exceedingly desolate, extremely empty

(adjective)

Nominative, masculine, singular of atyantaniḥśūnya

atyantaniḥśūnya - exceedingly desolate, extremely empty

Compound type : Karmadhāraya (atyanta+niḥśūnya)

• atyanta – exceedingly, extremely, very much
  indeclinable
• niḥśūnya – empty, desolate, devoid of
  adjective
  Prefix: nis
  Root: śū (class 1)

क्वचित् (kvacit) - sometimes, somewhere, in some place

(indeclinable)

जनपदावृतः (janapadāvṛtaḥ) - surrounded by populated areas, covered with inhabited lands

(adjective)

Nominative, masculine, singular of janapadāvṛta

janapadāvṛta - covered with inhabited lands, surrounded by populated areas

Compound type : Tṛtīyā Tatpuruṣa (janapada+āvṛta)

• janapada – populated country, inhabited area, people's dwelling place
  noun (masculine)
• āvṛta – covered, surrounded, enveloped
  adjective
  Past Passive Participle
  Derived from root vṛ with upasarga ā-
  Prefix: ā
  Root: vṛ (class 1)

क्वचित् (kvacit) - sometimes, somewhere, in some place

(indeclinable)

श्वभ्रान्तगम्भीरः (śvabhrāntagambhīraḥ) - profoundly deep due to chasms, deep with chasms within

(adjective)

Nominative, masculine, singular of śvabhrāntagambhīra

śvabhrāntagambhīra - profoundly deep due to chasms, deep with chasms within

Compound type : Bahuvrīhi (śvabhra+anta+gambhīra)

• śvabhra – chasm, abyss, pit, cave
  noun (neuter)
• anta – end, edge, limit, interior
  noun (masculine)
• gambhīra – deep, profound, serious, grave
  adjective

क्वचित् (kvacit) - sometimes, somewhere, in some place

(indeclinable)

पातालभीषणः (pātālabhīṣaṇaḥ) - terrifying like the netherworld, dreadful like Pātāla

(adjective)

Nominative, masculine, singular of pātālabhīṣaṇa

pātālabhīṣaṇa - terrifying like the netherworld, dreadful like Pātāla

Compound type : Upamāna-pūrvapada Karmadhāraya (pātāla+bhīṣaṇa)

• pātāla – the netherworld, a mythical subterranean region
  noun (masculine)
• bhīṣaṇa – terrifying, dreadful, formidable
  adjective
  Derived from root bhī (to fear)
  Root: bhī (class 2)