योगवासिष्ठः yogavāsiṣṭhaḥ - book-2, chapter-18, verse-12

मनः प्रसादमायाति शरदीव महत्सरः ।
परं साम्यमुपादत्ते निर्मन्दर इवार्णवः ॥ १२ ॥

manaḥ prasādamāyāti śaradīva mahatsaraḥ ,
paraṃ sāmyamupādatte nirmandara ivārṇavaḥ 12

12. manaḥ prasādam āyāti śaradi iva mahat saraḥ
param sāmyam upādātte nirmandaraḥ iva arṇavaḥ

12. manaḥ śaradi mahat saraḥ iva prasādam āyāti.
nirmandaraḥ arṇavaḥ iva param sāmyam upādātte.

12. The mind attains serenity, like a great lake in autumn. It achieves supreme tranquility, like the ocean when the Mandara mountain is no longer churning it.

Words meanings summery:

• मनः (manaḥ) - mind, intellect, thought

• प्रसादम् (prasādam) - serenity, clarity, grace, favor

• आयाति (āyāti) - attains, comes to, approaches

• शरदि (śaradi) - in autumn

• इव (iva) - like, as, as if

• महत् (mahat) - great, large, vast

• सरः (saraḥ) - lake, pond

• परम् (param) - supreme, highest, ultimate

• साम्यम् (sāmyam) - tranquility, equilibrium, equality

• उपादात्ते (upādātte) - attains, takes up, accepts

• निर्मन्दरः (nirmandaraḥ) - without Mandara (mountain)

• इव (iva) - like, as, as if

• अर्णवः (arṇavaḥ) - ocean, sea

Words meanings and morphology

मनः (manaḥ) - mind, intellect, thought

(noun)

Nominative, neuter, singular of manas

manas - mind, intellect, thought, heart

प्रसादम् (prasādam) - serenity, clarity, grace, favor

(noun)

Accusative, masculine, singular of prasāda

prasāda - serenity, clearness, grace, favor, tranquility

action noun

From root SAD (to sit) with prefix PRA

Prefix: pra

Root: sad (class 1)

आयाति (āyāti) - attains, comes to, approaches

(verb)

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

From root YĀ (to go) with prefix Ā

Prefix: ā

Root: yā (class 2)

शरदि (śaradi) - in autumn

(noun)

Locative, feminine, singular of śarad

śarad - autumn

इव (iva) - like, as, as if

(indeclinable)

महत् (mahat) - great, large, vast

(adjective)

Nominative, neuter, singular of mahat

mahat - great, large, mighty, extensive

सरः (saraḥ) - lake, pond

(noun)

Nominative, neuter, singular of saras

saras - lake, pond, pool

परम् (param) - supreme, highest, ultimate

(adjective)

Accusative, neuter, singular of para

para - other, distant, supreme, ultimate, highest

साम्यम् (sāmyam) - tranquility, equilibrium, equality

(noun)

Accusative, neuter, singular of sāmya

sāmya - equality, impartiality, equilibrium, tranquility

From sama (equal) with suffix -ya

उपादात्ते (upādātte) - attains, takes up, accepts

(verb)

3rd person , singular, middle, present (laṭ) of upādā

From root DĀ (to give) with prefixes UPĀ + Ā

Prefixes: upā+ā

Root: dā (class 3)

निर्मन्दरः (nirmandaraḥ) - without Mandara (mountain)

(adjective)

Nominative, masculine, singular of nirmandara

nirmandara - without the Mandara mountain

Compound type : bahuvrīhi (nis+mandara)

• nis – without, out, free from
  indeclinable
• mandara – Mandara mountain (used for churning the ocean in mythology)
  proper noun (masculine)

इव (iva) - like, as, as if

(indeclinable)

अर्णवः (arṇavaḥ) - ocean, sea

(noun)

Nominative, masculine, singular of arṇava

arṇava - ocean, sea