योगवासिष्ठः yogavāsiṣṭhaḥ - book-1, chapter-17, verse-41

गच्छत्युपशमं तृष्णा कायव्यायामशान्तये ।
तमी घनतमःकृष्णा यथा रक्षोनिवृत्तये ॥ ४१ ॥

gacchatyupaśamaṃ tṛṣṇā kāyavyāyāmaśāntaye ,
tamī ghanatamaḥkṛṣṇā yathā rakṣonivṛttaye 41

41. gacchati upaśamam tṛṣṇā kāyavyāyāmaśāntaye
tamī ghanatamaḥkṛṣṇā yathā rakṣonivṛttaye

41. Craving (tṛṣṇā) subsides for the calming of bodily activity, just as the night (tamī), intensely dark with dense gloom, [arises] for the suppression of demonic forces.

Words meanings summery:

• गच्छति (gacchati) - subsides, comes to an end (goes, moves, proceeds, reaches, attains)

• उपशमम् (upaśamam) - cessation, state of calm (cessation, tranquility, calmness, peace, suppression)

• तृष्णा (tṛṣṇā) - craving (tṛṣṇā) (thirst, desire, craving, longing)

• कायव्यायामशान्तये (kāyavyāyāmaśāntaye) - for the calming of physical activity (for the cessation of bodily exertion)

• तमी (tamī) - night, profound darkness (night, darkness)

• घनतमःकृष्णा (ghanatamaḥkṛṣṇā) - black with dense darkness (intensely dark, black with dense gloom)

• यथा (yathā) - just as (just as, as, according to)

• रक्षोनिवृत्तये (rakṣonivṛttaye) - for the suppression of demonic forces (for the cessation of demons, for the repulsion of evil spirits)

Words meanings and morphology

गच्छति (gacchati) - subsides, comes to an end (goes, moves, proceeds, reaches, attains)

(verb)

3rd person , singular, active, present indicative (laṭ) of gam

Present Active Indicative

Root gam, 1st conjugation (bhvādi), parasmaipada

Root: gam (class 1)

उपशमम् (upaśamam) - cessation, state of calm (cessation, tranquility, calmness, peace, suppression)

(noun)

Accusative, neuter, singular of upaśama

upaśama - cessation, quietude, tranquility, pacification

Derived from upa (prefix) + root śam (to be calm)

Prefix: upa

Root: śam (class 4)

Note: Functions as an adverbial accusative here, indicating the state attained.

तृष्णा (tṛṣṇā) - craving (tṛṣṇā) (thirst, desire, craving, longing)

(noun)

Nominative, feminine, singular of tṛṣṇā

tṛṣṇā - thirst, craving, desire, longing, greed

From root tṛṣ (to be thirsty)

Root: tṛṣ (class 4)

Note: Subject of the sentence.

कायव्यायामशान्तये (kāyavyāyāmaśāntaye) - for the calming of physical activity (for the cessation of bodily exertion)

(noun)

Dative, feminine, singular of kāyavyāyāmaśānti

kāyavyāyāmaśānti - cessation of bodily exertion/activity

Tatpurusha compound

Compound type : tatpuruṣa (kāya+vyāyāma+śānti)

• kāya – body, mass, collection
  noun (masculine)
• vyāyāma – exertion, effort, exercise, activity
  noun (masculine)
  From vi + ā + root yam (to restrain, stretch)
  Prefixes: vi+ā
  Root: yam (class 1)
• śānti – peace, tranquility, cessation, calming
  noun (feminine)
  From root śam (to be calm)
  Root: śam (class 4)

Note: Purpose.

तमी (tamī) - night, profound darkness (night, darkness)

(noun)

Nominative, feminine, singular of tamī

tamī - night, darkness

Note: Subject of the analogy.

घनतमःकृष्णा (ghanatamaḥkṛṣṇā) - black with dense darkness (intensely dark, black with dense gloom)

(adjective)

Nominative, feminine, singular of ghanatamaḥkṛṣṇa

ghanatamaḥkṛṣṇa - black/dark due to dense darkness

Bahuvrīhi compound

Compound type : bahuvrīhi (ghana+tamas+kṛṣṇa)

• ghana – dense, thick, solid; cloud
  adjective (masculine)
• tamas – darkness, gloom, ignorance
  noun (neuter)
• kṛṣṇa – black, dark blue; dark-colored
  adjective (masculine)

Note: Qualifies tamī.

यथा (yathā) - just as (just as, as, according to)

(indeclinable)

Note: Introduces the comparison.

रक्षोनिवृत्तये (rakṣonivṛttaye) - for the suppression of demonic forces (for the cessation of demons, for the repulsion of evil spirits)

(noun)

Dative, feminine, singular of rakṣonivṛtti

rakṣonivṛtti - cessation/repulsion of demons

Tatpurusha compound

Compound type : ṣaṣṭhī-tatpuruṣa (rakṣas+nivṛtti)

• rakṣas – demon, evil spirit, monster
  noun (neuter)
• nivṛtti – cessation, abstention, turning back, withdrawal, suppression
  noun (feminine)
  From ni + root vṛt (to turn)
  Prefix: ni
  Root: vṛt (class 1)

Note: Purpose.