योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-166, verse-13

नसंधिबन्धा निबिडा वज्रसारा विसारिणी ।
अत्यन्तपुष्टकठिनजठराकाशनिर्मला ॥ १३ ॥

nasaṃdhibandhā nibiḍā vajrasārā visāriṇī ,
atyantapuṣṭakaṭhinajaṭharākāśanirmalā 13

13. na-sandhi-bandhā nibiḍā vajra-sārā visāriṇī
atyanta-puṣṭa-kaṭhina-jaṭhara-ākāśa-nirmalā

13. na-sandhi-bandhā nibiḍā vajra-sārā visāriṇī
atyanta-puṣṭa-kaṭhina-jaṭhara-ākāśa-nirmalā

13. It is not bound by connections, dense, adamantine, and pervading. It is extremely robust, hard, compact in its core, and as pure as space (ākāśa).

Words meanings summery:

• न-सन्धि-बन्धा (na-sandhi-bandhā) - not bound by joints or connections

• निबिडा (nibiḍā) - dense, compact, firm

• वज्र-सारा (vajra-sārā) - having the hardness of a diamond, adamantine

• विसारिणी (visāriṇī) - pervading, spreading, extending

• अत्यन्त-पुष्ट-कठिन-जठर-आकाश-निर्मला (atyanta-puṣṭa-kaṭhina-jaṭhara-ākāśa-nirmalā) - extremely robust, hard, having a compact core/interior, and as pure as space

Words meanings and morphology

न-सन्धि-बन्धा (na-sandhi-bandhā) - not bound by joints or connections

(adjective)

Nominative, feminine, singular of na-sandhi-bandha

na-sandhi-bandha - not bound by joints; without connections

Compound type : Bahuvrihi (na+sandhi+bandha)

• na – not, no
  indeclinable
• sandhi – union, connection, joint
  noun (masculine)
  from sam-dhā, 'to put together'
  Prefix: sam
  Root: dhā (class 3)
• bandha – bond, tie, connection
  noun (masculine)
  from bandh, 'to bind'
  Root: bandh (class 1)

निबिडा (nibiḍā) - dense, compact, firm

(adjective)

Nominative, feminine, singular of nibiḍa

nibiḍa - dense, compact, firm, thick

वज्र-सारा (vajra-sārā) - having the hardness of a diamond, adamantine

(adjective)

Nominative, feminine, singular of vajra-sāra

vajra-sāra - diamond-hard, adamantine; essence of a thunderbolt

Compound type : Bahuvrihi (vajra+sāra)

• vajra – thunderbolt, diamond
  noun (neuter)
• sāra – essence, core, strength, hard part
  noun (masculine)
  Root: sṛ (class 1)

विसारिणी (visāriṇī) - pervading, spreading, extending

(adjective)

Nominative, feminine, singular of visārin

visārin - spreading, extending, pervading

Present Active Participle

from vi-sṛ (to spread out) + ṇin suffix

Prefix: vi

Root: sṛ (class 1)

अत्यन्त-पुष्ट-कठिन-जठर-आकाश-निर्मला (atyanta-puṣṭa-kaṭhina-jaṭhara-ākāśa-nirmalā) - extremely robust, hard, having a compact core/interior, and as pure as space

(adjective)

Nominative, feminine, singular of atyanta-puṣṭa-kaṭhina-jaṭhara-ākāśa-nirmala

atyanta-puṣṭa-kaṭhina-jaṭhara-ākāśa-nirmala - exceedingly firm and hard, with a strong interior, pure as space

Compound type : Karmadhāraya/Bahuvrihi (atyanta+puṣṭa+kaṭhina+jaṭhara+ākāśa+nirmala)

• atyanta – exceedingly, extremely, very much
  indeclinable
  ati + anta
  Prefix: ati
  Root: i (class 2)
• puṣṭa – nourished, strong, robust, full
  adjective
  Past Passive Participle
  from puṣ (to nourish, strengthen)
  Root: puṣ (class 1)
• kaṭhina – hard, firm, rigid, difficult
  adjective
• jaṭhara – belly, abdomen, interior, core
  noun (neuter)
• ākāśa – sky, space, ether
  noun (masculine)
  from ā-kāś (to shine upon) or ā-kāś (to appear)
  Prefix: ā
  Root: kāś (class 1)
• nirmala – spotless, pure, clear, clean
  adjective
  nis + mala (without impurity)
  Prefix: nis

Note: The entire compound describes a quality of the feminine singular subject.