योगवासिष्ठः yogavāsiṣṭhaḥ - book-3, chapter-54, verse-52

पूर्वापरं न जानाति स्मृतिस्तानवमागता ।
यथा पाश्चात्यसंध्यान्ते नष्टा दृष्टिर्दिगष्टके ॥ ५२ ॥

pūrvāparaṃ na jānāti smṛtistānavamāgatā ,
yathā pāścātyasaṃdhyānte naṣṭā dṛṣṭirdigaṣṭake 52

52. pūrvāparam na jānāti smṛtiḥ tānavam āgatā yathā
pāścātyasaṃdhyā-ante naṣṭā dṛṣṭiḥ dig-aṣṭake

52. tānavam āgatā smṛtiḥ pūrvāparam na jānāti yathā
pāścātyasaṃdhyā-ante digaṣṭake naṣṭā dṛṣṭiḥ

52. Memory (smṛti), having grown weak, no longer discerns the past and future, just as vision (dṛṣṭi) is lost in the eight directions at the end of the western twilight.

Words meanings summery:

• पूर्वापरम् (pūrvāparam) - the past and the future (in relation to memory) (past and future, former and latter, cause and effect)

• न (na) - not, no

• जानाति (jānāti) - discerns (knows, understands, perceives)

• स्मृतिः (smṛtiḥ) - memory, recollection, tradition

• तानवम् (tānavam) - weakness, feebleness (thinness, weakness, emaciation, slightness)

• आगता (āgatā) - having attained (weakness), having become (weak) (having come, arrived, attained)

• यथा (yathā) - just as, as, like

• पाश्चात्यसंध्या-अन्ते (pāścātyasaṁdhyā-ante) - at the end of the western twilight

• नष्टा (naṣṭā) - lost, destroyed, vanished

• दृष्टिः (dṛṣṭiḥ) - sight, vision, view, eye

• दिग्-अष्टके (dig-aṣṭake) - in the eight directions

Words meanings and morphology

पूर्वापरम् (pūrvāparam) - the past and the future (in relation to memory) (past and future, former and latter, cause and effect)

(noun)

Accusative, neuter, singular of pūrvāpara

pūrvāpara - former and latter, prior and posterior, cause and effect, past and future

Dvanda compound of pūrva (former) and apara (latter)

Compound type : dvandva (pūrva+apara)

• pūrva – previous, prior, former, eastern
  adjective (masculine)
• apara – other, subsequent, later, western
  adjective (masculine)

Note: Direct object of 'jānāti'.

न (na) - not, no

(indeclinable)

Note: Negates the verb.

जानाति (jānāti) - discerns (knows, understands, perceives)

(verb)

3rd person , singular, active, present (laṭ) of jñā

Root: jñā (class 9)

स्मृतिः (smṛtiḥ) - memory, recollection, tradition

(noun)

Nominative, feminine, singular of smṛti

smṛti - memory, recollection, tradition, code of law (dharmaśāstra)

Derived from root smṛ- 'to remember'

Root: smṛ (class 1)

Note: Subject of 'jānāti'.

तानवम् (tānavam) - weakness, feebleness (thinness, weakness, emaciation, slightness)

(noun)

Accusative, neuter, singular of tānava

tānava - thinness, weakness, slightness, feebleness

Derived from tanu (thin) + -a suffix

Note: Object of 'āgatā'.

आगता (āgatā) - having attained (weakness), having become (weak) (having come, arrived, attained)

(participle)

Nominative, feminine, singular of āgata

āgata - come, arrived, attained

Past Passive Participle

Derived from root gam- 'to go' with prefix ā-

Prefix: ā

Root: gam (class 1)

Note: Acts as an adjective for 'smṛtiḥ'.

यथा (yathā) - just as, as, like

(indeclinable)

Note: Introduces the simile.

पाश्चात्यसंध्या-अन्ते (pāścātyasaṁdhyā-ante) - at the end of the western twilight

(noun)

Locative, masculine, singular of pāścātyasaṃdhyā-anta

pāścātyasaṁdhyā-anta - end of the western twilight/dusk

Tatpurusha compound: pāścātyasaṃdhyā (western twilight) + anta (end)

Compound type : tatpurusha (pāścātyasaṃdhyā+anta)

• pāścātyasaṃdhyā – western twilight/dusk
  noun (feminine)
  Compound: pāścātya (western) + saṃdhyā (twilight)
• anta – end, limit, boundary
  noun (masculine)

Note: Specifies time/place.

नष्टा (naṣṭā) - lost, destroyed, vanished

(participle)

Nominative, feminine, singular of naṣṭa

naṣṭa - lost, destroyed, vanished, disappeared

Past Passive Participle

Derived from root naś- 'to perish, be lost'

Root: naś (class 4)

Note: Predicative adjective for 'dṛṣṭiḥ'.

दृष्टिः (dṛṣṭiḥ) - sight, vision, view, eye

(noun)

Nominative, feminine, singular of dṛṣṭi

dṛṣṭi - sight, vision, eye, view, intelligence

Derived from root dṛś- 'to see'

Root: dṛś (class 1)

Note: Subject of the comparison.

दिग्-अष्टके (dig-aṣṭake) - in the eight directions

(noun)

Locative, neuter, singular of digaṣṭaka

digaṣṭaka - group of eight directions

Tatpurusha compound: diś (direction) + aṣṭaka (group of eight)

Compound type : tatpurusha (diś+aṣṭaka)

• diś – direction, quarter of the sky
  noun (feminine)
  Root: diś (class 6)
• aṣṭaka – group of eight, eight-fold
  noun (neuter)

Note: Specifies location.