योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-138, verse-21

यदा तदात्मकात्मैकपरो हृदि सहस्थितम् ।
अप्रधानीकरोत्येतच्चित्तं स्वार्थस्वभावतः ॥ २१ ॥

yadā tadātmakātmaikaparo hṛdi sahasthitam ,
apradhānīkarotyetaccittaṃ svārthasvabhāvataḥ 21

21. yadā tadātmakātmaikaparō hṛdi sahastitam
apradhānīkarōti etat cittam svārthasvabhāvataḥ

21. yadā hṛdi sahastitam tadātmakātmaikaparō (cittam)
svārthasvabhāvataḥ etat cittam apradhānīkarōti

21. When the mind (citta), fixed solely on the unique (eka) Self (ātman) that is its very essence and resides within the heart (hṛdi) alongside it, then, by its inherent nature to seek its true purpose (sva-artha), it renders this (limited) mind secondary.

Words meanings summery:

• यदा (yadā) - when, at which time

• तदात्मकात्मैकपर्ओ (tadātmakātmaikaparō) - describing the mind's state of absorption in the Self (solely devoted to the one Self, which is its very nature)

• हृदि (hṛdi) - in the heart, in the mind

• सहस्तितम् (sahastitam) - referring to the Self (ātman) residing together with the mind in the heart (co-located, residing together, standing with)

• अप्रधानीकर्ओति (apradhānīkarōti) - makes secondary, renders unimportant, subordinates

• एतत् (etat) - referring to the limited, ego-bound mind that is made secondary (this, this one)

• चित्तम् (cittam) - the (limited) mind/ego that becomes secondary (mind, consciousness, thought)

• स्वार्थस्वभावतः (svārthasvabhāvataḥ) - by the intrinsic nature of the mind to seek its true, ultimate purpose (which is the Self) (by its own nature of seeking its purpose/interest)

Words meanings and morphology

यदा (yadā) - when, at which time

(indeclinable)

तदात्मकात्मैकपर्ओ (tadātmakātmaikaparō) - describing the mind's state of absorption in the Self (solely devoted to the one Self, which is its very nature)

(adjective)

Nominative, masculine, singular of tadātmakātmaikaparō

tadātmakātmaikaparā - solely devoted to the one Self, which is of that nature

Compound adjective, masculine nominative singular.

Compound type : bahuvrīhi-tatpuruṣa (tadātmaka+ātmaika+para)

• tadātmaka – having that as its nature, being of that nature
  adjective (masculine)
  Compound 'tad' (that) + 'ātmaka' (nature, essence).
• ātmaika – the one Self (ātman)
  noun (masculine)
  Compound 'ātman' (Self) + 'eka' (one).
• para – devoted, intent on, supreme, other
  adjective (masculine)

हृदि (hṛdi) - in the heart, in the mind

(noun)

Locative, neuter, singular of hṛd

hṛd - heart, mind, core, essence

सहस्तितम् (sahastitam) - referring to the Self (ātman) residing together with the mind in the heart (co-located, residing together, standing with)

(adjective)

Accusative, neuter, singular of sahastita

sahastita - standing together, co-located

Past Passive Participle

From 'saha' (with, together) and 'sthita' (PPP of 'sthā', stood, situated).

Compound type : avyayībhāva (saha+sthita)

• saha – with, together
  indeclinable
• sthita – stood, situated, existing
  adjective (masculine)
  Past Passive Participle
  From root 'sthā' (to stand).
  Root: sthā (class 1)

Note: Agrees with an implied 'ātman' or refers to 'cittam' in an adverbial sense.

अप्रधानीकर्ओति (apradhānīkarōti) - makes secondary, renders unimportant, subordinates

(verb)

3rd person , singular, active, present (lat) of apradhānīkṛ

Denominative or causative-like formation with 'kṛ'

Formed from 'a-pradhāna' (not primary, secondary) + 'ī-kṛ' (to make into). Present tense, 3rd person singular, active voice.

Root: kṛ (class 8)

एतत् (etat) - referring to the limited, ego-bound mind that is made secondary (this, this one)

(pronoun)

Accusative, neuter, singular of etas

etas - this, this one

चित्तम् (cittam) - the (limited) mind/ego that becomes secondary (mind, consciousness, thought)

(noun)

Accusative, neuter, singular of citta

citta - mind, consciousness, thought, intellect

Root: cit (class 1)

स्वार्थस्वभावतः (svārthasvabhāvataḥ) - by the intrinsic nature of the mind to seek its true, ultimate purpose (which is the Self) (by its own nature of seeking its purpose/interest)

(noun)

Ablative, masculine, singular of svārthasvabhāva

svārthasvabhāva - nature of its own purpose/interest

Compound 'sva-artha' (self-interest, true purpose) + 'sva-bhāva' (own nature). Ablative singular.

Compound type : tatpuruṣa (sva-artha+svabhāva)

• sva-artha – own purpose, self-interest, true goal
  noun (masculine)
  Compound 'sva' (own) + 'artha' (purpose, meaning, object).
• svabhāva – own nature, intrinsic quality, essential property
  noun (masculine)
  Compound 'sva' (own) + 'bhāva' (nature, state of being).
  Prefix: sva
  Root: bhū (class 1)