योगवासिष्ठः yogavāsiṣṭhaḥ - book-2, chapter-15, verse-15

संतोषाऽमृतपूर्णस्य शान्तशीतलया धिया ।
स्वयं स्थैर्यं मनो याति शीतांशोरिव शाश्वतम् ॥ १५ ॥

saṃtoṣā'mṛtapūrṇasya śāntaśītalayā dhiyā ,
svayaṃ sthairyaṃ mano yāti śītāṃśoriva śāśvatam 15

15. saṃtoṣāmṛtapūrṇasya śāntaśītalayā dhiyā svayam
sthairyam manaḥ yāti śītāṃśoḥ iva śāśvatam

15. saṃtoṣāmṛtapūrṇasya śāntaśītalayā dhiyā,
manaḥ svayam śītāṃśoḥ iva śāśvatam sthairyam yāti

15. By the peaceful and serene intellect (dhī) of a person who is filled with the nectar of contentment (saṃtoṣa), the mind (manas) itself attains eternal stability (sthairya), just like the perpetual calm of the moon.

Words meanings summery:

• संतोषामृतपूर्णस्य (saṁtoṣāmṛtapūrṇasya) - of one filled with the nectar of contentment

• शान्तशीतलया (śāntaśītalayā) - by a peaceful and cool

• धिया (dhiyā) - by intellect, by understanding, by mind (dhī)

• स्वयम् (svayam) - by itself, oneself

• स्थैर्यम् (sthairyam) - stability, steadiness, firmness

• मनः (manaḥ) - mind, intellect, thought (manas)

• याति (yāti) - goes, attains, reaches

• शीतांशोः (śītāṁśoḥ) - of the moon (lit. 'cold-rayed')

• इव (iva) - like, as, as if

• शाश्वतम् (śāśvatam) - eternal, perpetual, constant

Words meanings and morphology

संतोषामृतपूर्णस्य (saṁtoṣāmṛtapūrṇasya) - of one filled with the nectar of contentment

(adjective)

Genitive, masculine, singular of saṃtoṣāmṛtapūrṇa

saṁtoṣāmṛtapūrṇa - filled with the nectar of contentment

Bahuvrihi compound: saṃtoṣāmṛta (nectar of contentment) + pūrṇa (filled)

Compound type : bahuvrīhi (saṃtoṣa+amṛta+pūrṇa)

• saṃtoṣa – contentment, satisfaction (saṃtoṣa)
  noun (masculine)
  Derived from root tuṣ with upasarga sam
  Prefix: sam
  Root: tuṣ (class 4)
• amṛta – nectar, immortality
  noun (neuter)
  Prefix: a
• pūrṇa – full, filled, complete
  adjective
  Past Passive Participle
  Derived from the root pṛ (to fill)
  Root: pṛ (class 9)

शान्तशीतलया (śāntaśītalayā) - by a peaceful and cool

(adjective)

Instrumental, feminine, singular of śāntaśītalā

śāntaśītalā - peaceful and cool

Dvandva compound

Compound type : dvandva (śānta+śītalā)

• śānta – calm, peaceful, tranquil
  adjective
  Past Passive Participle
  Derived from the root śam (to be calm)
  Root: śam (class 4)
• śītalā – cool, cold
  adjective (feminine)

धिया (dhiyā) - by intellect, by understanding, by mind (dhī)

(noun)

Instrumental, feminine, singular of dhī

dhī - intellect, thought, understanding, mind

Root: dhī (class 3)

स्वयम् (svayam) - by itself, oneself

(indeclinable)

स्थैर्यम् (sthairyam) - stability, steadiness, firmness

(noun)

Accusative, neuter, singular of sthairya

sthairya - stability, steadiness, firmness

Derived from sthira (firm) + ya (suffix for abstract noun)

मनः (manaḥ) - mind, intellect, thought (manas)

(noun)

Nominative, neuter, singular of manas

manas - mind, intellect, thought, consciousness

याति (yāti) - goes, attains, reaches

(verb)

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

Root: yā (class 2)

शीतांशोः (śītāṁśoḥ) - of the moon (lit. 'cold-rayed')

(noun)

Genitive, masculine, singular of śītāṃśu

śītāṁśu - moon (lit. 'cold-rayed')

Compound: śīta + aṃśu

Compound type : bahuvrīhi (śīta+aṃśu)

• śīta – cold, cool
  adjective
• aṃśu – ray, beam of light
  noun (masculine)

इव (iva) - like, as, as if

(indeclinable)

शाश्वतम् (śāśvatam) - eternal, perpetual, constant

(adjective)

Accusative, neuter, singular of śāśvata

śāśvata - eternal, perpetual, constant, everlasting