योगवासिष्ठः yogavāsiṣṭhaḥ - book-4, chapter-19, verse-12

स्वप्नोऽपि स्वप्नसमये स्थैर्याज्जाग्रत्त्वमृच्छति ।
अस्थैर्याज्जाग्रदेवास्ते स्वप्नस्तादृशबोधतः ॥ १२ ॥

svapno'pi svapnasamaye sthairyājjāgrattvamṛcchati ,
asthairyājjāgradevāste svapnastādṛśabodhataḥ 12

12. svapnaḥ api svapnasamaye sthairyāt jāgrattvaṃ ṛcchati
asthairyāt jāgrat eva āste svapnaḥ tādṛśabodhataḥ

12. svapnaḥ api svapnasamaye sthairyāt jāgrattvaṃ ṛcchati
jāgrat eva asthairyāt tādṛśabodhataḥ svapnaḥ āste

12. Even a dream, during its own period, attains the nature of the waking state due to its (perceived) stability. Conversely, the waking state itself is understood as a dream, due to its impermanence and a similar kind of perception (as in a dream).

Words meanings summery:

• स्वप्नः (svapnaḥ) - dream, sleep

• अपि (api) - also, even, too

• स्वप्नसमये (svapnasamaye) - in the time of dream, during a dream

• स्थैर्यात् (sthairyāt) - due to its perceived stability (within the dream) (due to stability, from permanence)

• जाग्रत्त्वं (jāgrattvaṁ) - waking-ness, the state of being awake

• ऋच्छति (ṛcchati) - attains, reaches, goes to

• अस्थैर्यात् (asthairyāt) - due to impermanence, from instability

• जाग्रत् (jāgrat) - the waking state (waking, awake)

• एव (eva) - indeed, only, just

• आस्ते (āste) - is, exists (as a dream) (sits, stays, exists, is)

• स्वप्नः (svapnaḥ) - dream, sleep

• तादृशबोधतः (tādṛśabodhataḥ) - due to such a perception/understanding

Words meanings and morphology

स्वप्नः (svapnaḥ) - dream, sleep

(noun)

Nominative, masculine, singular of svapna

svapna - sleep, dream

Derived from root svap (to sleep).

Root: svap (class 2)

अपि (api) - also, even, too

(indeclinable)

स्वप्नसमये (svapnasamaye) - in the time of dream, during a dream

(noun)

Locative, masculine, singular of svapnasamaya

svapnasamaya - dream time, period of a dream

Compound type : tatpuruṣa (svapna+samaya)

• svapna – sleep, dream
  noun (masculine)
  Derived from root svap (to sleep).
  Root: svap (class 2)
• samaya – time, occasion, period, convention
  noun (masculine)

स्थैर्यात् (sthairyāt) - due to its perceived stability (within the dream) (due to stability, from permanence)

(noun)

Ablative, neuter, singular of sthairya

sthairya - stability, permanence, firmness, steadfastness

Derived from sthira (firm, stable) + -ya (nominal suffix).

जाग्रत्त्वं (jāgrattvaṁ) - waking-ness, the state of being awake

(noun)

Accusative, neuter, singular of jāgrattva

jāgrattva - waking-ness, the state of being awake

Derived from jāgrat (waking) + -tva (nominal suffix).

ऋच्छति (ṛcchati) - attains, reaches, goes to

(verb)

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

Present Indicative Active 3rd Person Singular

Root ṛ, class 6, pres. stem ṛccha-.

Root: ṛ (class 6)

अस्थैर्यात् (asthairyāt) - due to impermanence, from instability

(noun)

Ablative, neuter, singular of asthairya

asthairya - instability, impermanence

Derived from asthira (unstable, impermanent) + -ya (nominal suffix).

Compound type : nañ-tatpuruṣa (a+sthairya)

• a – not, un-
  indeclinable
• sthairya – stability, permanence
  noun (neuter)

जाग्रत् (jāgrat) - the waking state (waking, awake)

(adjective)

Nominative, singular of jāgrat

jāgrat - waking, awake, alert

Present Active Participle

Derived from root jājṛ (to wake) in present active participle form.

Root: jājṛ (class 2)

Note: Used substantively to refer to the waking state.

एव (eva) - indeed, only, just

(indeclinable)

आस्ते (āste) - is, exists (as a dream) (sits, stays, exists, is)

(verb)

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

Present Indicative Middle 3rd Person Singular

Root ās, class 2, middle voice.

Root: ās (class 2)

स्वप्नः (svapnaḥ) - dream, sleep

(noun)

Nominative, masculine, singular of svapna

svapna - sleep, dream

Derived from root svap (to sleep).

Root: svap (class 2)

तादृशबोधतः (tādṛśabodhataḥ) - due to such a perception/understanding

(noun)

Ablative, masculine, singular of tādṛśabodha

tādṛśabodha - such a perception/understanding

Derived from tādṛśa (such) and bodha (perception).

Compound type : karmadhāraya (tādṛśa+bodha)

• tādṛśa – such, of that kind
  adjective
• bodha – perception, understanding, awakening
  noun (masculine)
  Derived from root budh (to know, perceive).
  Root: budh (class 1)

Note: Suffix -tas indicates cause/source.