योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-102, verse-41

नित्यान्तःशीतलो मौनी सत्त्वीभूतमनोवनिः ।
परिपूर्णार्णवाकारो गम्भीरप्रकटाशयः ॥ ४१ ॥

nityāntaḥśītalo maunī sattvībhūtamanovaniḥ ,
paripūrṇārṇavākāro gambhīraprakaṭāśayaḥ 41

41. nityāntaḥ-śītalaḥ maunī sattvībhūta-mano-vaniḥ
paripūrṇa-arṇava-ākāraḥ gambhīra-prakaṭa-āśayaḥ

41. (saḥ) nityāntaḥ-śītalaḥ,
maunī,
sattvībhūta-mano-vaniḥ,
paripūrṇa-arṇava-ākāraḥ,
gambhīra-prakaṭa-āśayaḥ (asti)

41. He is ever inwardly calm, a silent ascetic (maunī), whose mental landscape is transformed into pure essence (sattva), appearing like a completely full ocean, and whose profound intentions are clearly evident.

Words meanings summery:

• नित्यान्तः-शीतलः (nityāntaḥ-śītalaḥ) - ever inwardly cool/calm

• मौनी (maunī) - silent one, ascetic who observes silence

• सत्त्वीभूत-मनो-वनिः (sattvībhūta-mano-vaniḥ) - whose mind-forest has become pure essence (sattva)

• परिपूर्ण-अर्णव-आकारः (paripūrṇa-arṇava-ākāraḥ) - having the form of a completely full ocean

• गम्भीर-प्रकट-आशयः (gambhīra-prakaṭa-āśayaḥ) - whose profound intentions are manifest

Words meanings and morphology

नित्यान्तः-शीतलः (nityāntaḥ-śītalaḥ) - ever inwardly cool/calm

(adjective)

Nominative, masculine, singular of nityāntaḥ-śītala

nityāntaḥ-śītala - one who is always internally cool or calm

Compound type : Bahuvrīhi (nitya+antas+śītala)

• nitya – eternal, constant, always
  adjective
• antas – inside, inner part, interior
  noun (neuter)
• śītala – cool, cold, calm, tranquil
  adjective

मौनी (maunī) - silent one, ascetic who observes silence

(noun)

Nominative, masculine, singular of maunin

maunin - silent, ascetic, sage, observer of silence

सत्त्वीभूत-मनो-वनिः (sattvībhūta-mano-vaniḥ) - whose mind-forest has become pure essence (sattva)

(adjective)

Nominative, masculine, singular of sattvībhūta-mano-vani

sattvībhūta-mano-vani - one whose mind (manas), conceived as a forest (vani), has become (bhūta) sattva (purity/essence)

Compound type : Bahuvrīhi (sattva+bhūta+manas+vani)

• sattva – essence, reality, purity, goodness (a guṇa)
  noun (neuter)
• bhūta – become, existed, happened
  adjective
  Past Passive Participle
  Root: bhū
• manas – mind, intellect, thought
  noun (neuter)
• vani – forest, wood
  noun (feminine)

परिपूर्ण-अर्णव-आकारः (paripūrṇa-arṇava-ākāraḥ) - having the form of a completely full ocean

(adjective)

Nominative, masculine, singular of paripūrṇa-arṇava-ākāra

paripūrṇa-arṇava-ākāra - one who has the appearance or form of a completely full ocean

Compound type : Bahuvrīhi (paripūrṇa+arṇava+ākāra)

• paripūrṇa – completely full, perfect, satisfied
  adjective
  Past Passive Participle
  Prefix: pari
  Root: pṝ
• arṇava – ocean, sea
  noun (masculine)
• ākāra – form, shape, appearance
  noun (masculine)

गम्भीर-प्रकट-आशयः (gambhīra-prakaṭa-āśayaḥ) - whose profound intentions are manifest

(adjective)

Nominative, masculine, singular of gambhīra-prakaṭa-āśaya

gambhīra-prakaṭa-āśaya - one whose deep and manifest thoughts or intentions (āśaya) are revealed or clear

Compound type : Bahuvrīhi (gambhīra+prakaṭa+āśaya)

• gambhīra – deep, profound, serious
  adjective
• prakaṭa – manifest, apparent, clear, evident
  adjective
  Past Passive Participle
  derived from the root `kaṭ` (to go, move) with prefix `pra`, meaning 'made evident, manifested'
  Prefix: pra
  Root: kaṭ (class 1)
• āśaya – intention, purpose, meaning, repository, mind
  noun (masculine)