योगवासिष्ठः yogavāsiṣṭhaḥ - book-6, chapter-55, verse-3

देहनाशे महाबाहो न किंचिदपि नश्यति ।
आत्मनाशो हि नाशः स्यान्न चात्मा नश्यति ध्रुवः ॥ ३ ॥

dehanāśe mahābāho na kiṃcidapi naśyati ,
ātmanāśo hi nāśaḥ syānna cātmā naśyati dhruvaḥ 3

3. dehanāśe mahābāho na kiṃcit api naśyati ātmanāśaḥ
hi nāśaḥ syāt na ca ātmā naśyati dhruvaḥ

3. mahābāho dehanāśe na kiṃcit api naśyati ātmanāśaḥ
hi nāśaḥ syāt ca na dhruvaḥ ātmā naśyati

3. O mighty-armed one, when the body perishes, nothing at all is truly destroyed. Indeed, only the destruction of the self (ātman) would constitute destruction, but the self (ātman) is eternal and does not perish.

Words meanings summery:

• देहनाशे (dehanāśe) - in the destruction of the body, at the body's perishing

• महाबाहो (mahābāho) - An epithet for Arjuna, addressed by Krishna. (O mighty-armed one, O great-armed one)

• न (na) - not, no

• किंचित् (kiṁcit) - Used with na to mean 'nothing at all'. (something, anything)

• अपि (api) - Emphasizes 'not even a little'. (also, even, too)

• नश्यति (naśyati) - perishes, is destroyed, is lost

• आत्मनाशः (ātmanāśaḥ) - The ultimate destruction, which is impossible for the true ātman. (destruction of the self (ātman))

• हि (hi) - Emphasizes the statement. (indeed, surely, because)

• नाशः (nāśaḥ) - The actual definition of destruction. (destruction, perishing, loss)

• स्यात् (syāt) - Indicates a hypothetical or potential outcome. (it would be, it might be, let it be)

• न (na) - not, no

• च (ca) - Introduces a contrasting statement. (and, but, also)

• आत्मा (ātmā) - The ultimate, eternal self. (the self, the soul (ātman))

• नश्यति (naśyati) - perishes, is destroyed, is lost

• ध्रुवः (dhruvaḥ) - Describes the imperishable nature of the self (ātman). (eternal, constant, firm, fixed)

Words meanings and morphology

देहनाशे (dehanāśe) - in the destruction of the body, at the body's perishing

(noun)

Locative, masculine, singular of dehanāśa

dehanāśa - destruction of the body, body's ruin

Compound of deha (body) + nāśa (destruction).

Compound type : ṣaṣṭhī-tatpuruṣa (deha+nāśa)

• deha – body
  noun (masculine)
  From root dih (to smear, to grow).
  Root: dih (class 4)
• nāśa – destruction, perishing, loss
  noun (masculine)
  From root naś (to perish, to be lost).
  Root: naś (class 4)

Note: Denotes the time or occasion of the destruction.

महाबाहो (mahābāho) - An epithet for Arjuna, addressed by Krishna. (O mighty-armed one, O great-armed one)

(adjective)

Vocative, masculine, singular of mahābāhu

mahābāhu - mighty-armed, great-armed

Compound: mahā (great) + bāhu (arm). Used as a proper noun/epithet.

Compound type : bahuvrīhi (mahā+bāhu)

• mahā – great, large, mighty
  adjective (feminine)
  Feminine stem of mahat.
• bāhu – arm
  noun (masculine)

Note: Address to Arjuna.

न (na) - not, no

(indeclinable)

किंचित् (kiṁcit) - Used with na to mean 'nothing at all'. (something, anything)

(indeclinable)

Formed from kim (what) + cit (an indefinite particle).

अपि (api) - Emphasizes 'not even a little'. (also, even, too)

(indeclinable)

नश्यति (naśyati) - perishes, is destroyed, is lost

(verb)

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

Present active

Fourth class verb. Third person singular.

Root: naś (class 4)

Note: Subject is kiṃcit.

आत्मनाशः (ātmanāśaḥ) - The ultimate destruction, which is impossible for the true ātman. (destruction of the self (ātman))

(noun)

Nominative, masculine, singular of ātmanāśa

ātmanāśa - destruction of the self, self-destruction (of the individual ego, not the true self)

Compound of ātman (self) + nāśa (destruction).

Compound type : ṣaṣṭhī-tatpuruṣa (ātman+nāśa)

• ātman – self, soul, spirit, individual soul (ātman)
  noun (masculine)
  From root an (to breathe).
  Root: an (class 2)
• nāśa – destruction, perishing, loss
  noun (masculine)
  From root naś (to perish, to be lost).
  Root: naś (class 4)

Note: Subject of syāt.

हि (hi) - Emphasizes the statement. (indeed, surely, because)

(indeclinable)

An emphatic or explanatory particle.

नाशः (nāśaḥ) - The actual definition of destruction. (destruction, perishing, loss)

(noun)

Nominative, masculine, singular of nāśa

nāśa - destruction, perishing, loss, ruin

From root naś (to perish).

Root: naś (class 4)

स्यात् (syāt) - Indicates a hypothetical or potential outcome. (it would be, it might be, let it be)

(verb)

3rd person , singular, active, optative (vidhi-liṅ) of as

Optative active

Third person singular.

Root: as (class 2)

न (na) - not, no

(indeclinable)

च (ca) - Introduces a contrasting statement. (and, but, also)

(indeclinable)

Conjunction.

आत्मा (ātmā) - The ultimate, eternal self. (the self, the soul (ātman))

(noun)

Nominative, masculine, singular of ātman

ātman - self, soul, spirit, individual soul (ātman)

From root an (to breathe).

Root: an (class 2)

Note: Subject of naśyati.

नश्यति (naśyati) - perishes, is destroyed, is lost

(verb)

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

Present active

Fourth class verb. Third person singular.

Root: naś (class 4)

Note: Subject is kiṃcit.

ध्रुवः (dhruvaḥ) - Describes the imperishable nature of the self (ātman). (eternal, constant, firm, fixed)

(adjective)

Nominative, masculine, singular of dhruva

dhruva - firm, fixed, constant, eternal, unchangeable

From root dhru (to be firm).

Root: dhru (class 1)

Note: Predicate adjective for ātmā.