योगवासिष्ठः yogavāsiṣṭhaḥ - book-3, chapter-16, verse-21

तथा यते यत्नमतस्तपोजपयमेहितैः ।
रजनीशमुखो राजा यथा स्यादजरामरः ॥ २१ ॥

tathā yate yatnamatastapojapayamehitaiḥ ,
rajanīśamukho rājā yathā syādajarāmaraḥ 21

21. tathā yate yatnam ataḥ tapojapayamaihitaiah
rajanīśamukhaḥ rājā yathā syāt ajarāmaraḥ

21. aham tathā yatnam ataḥ tapojapayamaihitaiah
yate yathā rajanīśamukhaḥ rājā ajarāmaraḥ syāt

21. Thus, I strive with great effort, by means of ascetic practices (tapas), chanting (japa), and self-restraints (yama) that I undertake, so that the moon-faced king may become ageless and immortal.

Words meanings summery:

• तथा (tathā) - thus, so, in that manner

• यते (yate) - I strive, I endeavor, I attempt

• यत्नम् (yatnam) - effort (adverbially implying 'with effort') (effort, exertion, striving)

• अतः (ataḥ) - therefore (connecting the effort to the means) (from this, hence, therefore, on this account)

• तपोजपयमैहितैअह् (tapojapayamaihitaiah) - by ascetic practices (tapas), chanting (japa), and self-restraints (yama) that are desired/undertaken

• रजनीशमुखः (rajanīśamukhaḥ) - the moon-faced king (moon-faced)

• राजा (rājā) - king

• यथा (yathā) - so that, in order that, as, just as

• स्यात् (syāt) - may be, should be, may become

• अजरामरः (ajarāmaraḥ) - ageless and immortal

Words meanings and morphology

तथा (tathā) - thus, so, in that manner

(indeclinable)

यते (yate) - I strive, I endeavor, I attempt

(verb)

1st person , singular, middle, present (laṭ) of yat

Root: yat (class 1)

यत्नम् (yatnam) - effort (adverbially implying 'with effort') (effort, exertion, striving)

(noun)

Accusative, masculine, singular of yatna

yatna - effort, exertion, striving, endeavor

Root: yat (class 1)

Note: Here, it functions adverbially, meaning 'with effort'.

अतः (ataḥ) - therefore (connecting the effort to the means) (from this, hence, therefore, on this account)

(indeclinable)

तपोजपयमैहितैअह् (tapojapayamaihitaiah) - by ascetic practices (tapas), chanting (japa), and self-restraints (yama) that are desired/undertaken

(adjective)

Instrumental, masculine, plural of tapojapayamaihita

tapojapayamaihita - ascetic practices, chanting, and self-restraints that are sought/undertaken

Compound type : dvandva-tatpurusha (tapas+japa+yama+īhita)

• tapas – asceticism, austerity, penance (tapas)
  noun (neuter)
  Root: tap (class 1)
• japa – muttering prayers, chanting, recitation (japa)
  noun (masculine)
  Root: jap (class 1)
• yama – restraint, self-control (yama)
  noun (masculine)
  Root: yam (class 1)
• īhita – desired, wished, sought, undertaken
  adjective (neuter)
  Past Passive Participle
  Past passive participle of root īh (to strive, to desire).
  Root: īh (class 1)

Note: Qualifies the means by which she strives.

रजनीशमुखः (rajanīśamukhaḥ) - the moon-faced king (moon-faced)

(adjective)

Nominative, masculine, singular of rajanīśamukha

rajanīśamukha - moon-faced (one whose face is like the moon)

Compound type : bahuvrihi (rajanīśa+mukha)

• rajanīśa – lord of night, moon
  noun (masculine)
• mukha – face, mouth, countenance
  noun (neuter)

राजा (rājā) - king

(noun)

Nominative, masculine, singular of rājan

rājan - king, ruler

यथा (yathā) - so that, in order that, as, just as

(indeclinable)

स्यात् (syāt) - may be, should be, may become

(verb)

3rd person , singular, active, optative (vidhiliṅ) of as

Root: as (class 2)

अजरामरः (ajarāmaraḥ) - ageless and immortal

(adjective)

Nominative, masculine, singular of ajarāmara

ajarāmara - ageless and immortal

Compound type : dvandva (ajara+amara)

• ajara – not growing old, ageless, undecaying
  adjective
• amara – immortal, deathless
  adjective