योगवासिष्ठः yogavāsiṣṭhaḥ - book-2, chapter-18, verse-20

सर्वार्थशीतला शुद्धा परमालोकदास्यधीः ।
परं प्रकाशमायाति ज्योत्स्नेव शरदैन्दवी ॥ २० ॥

sarvārthaśītalā śuddhā paramālokadāsyadhīḥ ,
paraṃ prakāśamāyāti jyotsneva śaradaindavī 20

20. sarvārthaśītalā śuddhā paramālokadāsyadhīḥ |
param prakāśam āyāti jyotsnā iva śaradaidavī ||

20. sarvārthaśītalā śuddhā paramālokadāsyadhīḥ
śaradaidavī jyotsnā iva param prakāśam āyāti

20. The intellect (dhī) that is serene towards all objects, pure, and devoted to the supreme light, attains supreme manifestation, just like autumnal moonlight.

Words meanings summery:

• सर्वार्थशीतला (sarvārthaśītalā) - The intellect (dhī) which is calm and unagitated by all worldly objects or concerns. (serene for all purposes, cool towards all objects)

• शुद्धा (śuddhā) - pure, clean, undefiled

• परमालोकदास्यधीः (paramālokadāsyadhīḥ) - The understanding or consciousness dedicated to the highest reality or truth. (intellect whose service is to the supreme light, mind serving the ultimate illumination)

• परम् (param) - supreme, highest, ultimate

• प्रकाशम् (prakāśam) - Supreme manifestation or illumination. (light, manifestation, brilliance)

• आयाति (āyāti) - Achieves or manifests. (comes, attains, reaches)

• ज्योत्स्ना (jyotsnā) - moonlight, moonshine

• इव (iva) - like, as, as if

• शरदैदवी (śaradaidavī) - Pure and bright like the moonlight of autumn, which is typically clear. (autumnal, like the autumn moon)

Words meanings and morphology

सर्वार्थशीतला (sarvārthaśītalā) - The intellect (dhī) which is calm and unagitated by all worldly objects or concerns. (serene for all purposes, cool towards all objects)

(adjective)

Nominative, feminine, singular of sarvārthaśītala

sarvārthaśītala - cool or serene in regard to all objects/purposes

Compound.

Compound type : tatpurusha (sarva+artha+śītala)

• sarva – all, every
  adjective
• artha – object, purpose, meaning, wealth
  noun (masculine)
• śītala – cool, cold, serene, tranquil
  adjective (masculine)

Note: Agrees with dhīḥ.

शुद्धा (śuddhā) - pure, clean, undefiled

(adjective)

Nominative, feminine, singular of śuddha

śuddha - pure, clean, clear, undefiled, faultless

Past Passive Participle

From root śudh (to be pure, clean) + kta (ta) suffix.

Root: śudh (class 4)

Note: Agrees with dhīḥ.

परमालोकदास्यधीः (paramālokadāsyadhīḥ) - The understanding or consciousness dedicated to the highest reality or truth. (intellect whose service is to the supreme light, mind serving the ultimate illumination)

(noun)

Nominative, feminine, singular of paramālokadāsyadhī

paramālokadāsyadhī - intellect whose servitude is to the supreme light

Bahuvrīhi compound: one whose intellect is (a) service to the supreme light.

Compound type : bahuvrīhi (parama+āloka+dāsya+dhī)

• parama – supreme, highest, ultimate
  adjective (masculine)
• āloka – light, vision, perception, sight
  noun (masculine)
  From ā + root lok (to see)
  Prefix: ā
  Root: lok (class 10)
• dāsya – servitude, service, slavery
  noun (neuter)
  From dāsa (servant) + ṣya suffix.
• dhī – intellect, understanding, mind, thought
  noun (feminine)
  From root dhyai (to meditate) or dhā (to place).
  Root: dhyai (class 1)

Note: Main subject of the sentence.

परम् (param) - supreme, highest, ultimate

(adjective)

Accusative, neuter, singular of parama

parama - supreme, highest, ultimate, excellent

Superlative form of para.

Note: Agrees with prakāśam.

प्रकाशम् (prakāśam) - Supreme manifestation or illumination. (light, manifestation, brilliance)

(noun)

Accusative, neuter, singular of prakāśa

prakāśa - light, brilliance, manifestation, splendor, publicity

From pra + root kāś (to shine).

Prefix: pra

Root: kāś (class 1)

Note: Object of āyāti.

आयाति (āyāti) - Achieves or manifests. (comes, attains, reaches)

(verb)

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

present active, 3rd person singular

From ā + root yā (to go).

Prefix: ā

Root: yā (class 2)

ज्योत्स्ना (jyotsnā) - moonlight, moonshine

(noun)

Nominative, feminine, singular of jyotsnā

jyotsnā - moonlight, moonshine, night

From jyotis (light) + sna suffix.

Note: Part of the simile.

इव (iva) - like, as, as if

(indeclinable)

शरदैदवी (śaradaidavī) - Pure and bright like the moonlight of autumn, which is typically clear. (autumnal, like the autumn moon)

(adjective)

Nominative, feminine, singular of śaradaidava

śaradaidava - autumnal moonlight, relating to the autumn moon

Formed from śarad (autumn) and aindava (lunar, belonging to the moon).

Compound type : tatpurusha (śarad+aindava)

• śarad – autumn
  noun (feminine)
• aindava – lunar, pertaining to the moon
  adjective (masculine)
  Derived from indu (moon).

Note: Agrees with jyotsnā.