महाभारतः mahābhārataḥ - book-7, chapter-158, verse-2

यदाजानीत तां शक्तिमेकघ्नीं सततं रणे ।
अनिवार्यामसह्यां च देवैरपि सवासवैः ॥२॥

2. yadājānīta tāṁ śaktimekaghnīṁ satataṁ raṇe ,
anivāryāmasahyāṁ ca devairapi savāsavaiḥ.

2. yadā ajānīta tām śaktim ekaghnīm satatam raṇe
anivāryām asahām ca devaiḥ api savāsavaiḥ

2. yadā saḥ (he - implied agent for ajānīta) tām ekaghnīm satatam raṇe anivāryām asahām ca devaiḥ api savāsavaiḥ śaktim ajānīta.

2. When he realized that one-killing weapon (śakti), which was always present in battle, and which was irresistible and unbearable even for the gods, including Vasava (Indra).

Words meanings summery:

• यदा (yadā) - when, whenever

• अजानीत (ajānīta) - he knew, he recognized, he realized

• ताम् (tām) - that (feminine)

• शक्तिम् (śaktim) - the divine weapon (śakti) (power, strength, divine energy, weapon)

• एकघ्नीम् (ekaghnīm) - that specific weapon that can kill only one target (Indra's spear) (one-killing, slaying one (target))

• सततम् (satatam) - constantly, always, perpetually

• रणे (raṇe) - in battle, in war

• अनिवार्याम् (anivāryām) - irresistible, unavoidable, unpreventable

• असहाम् (asahām) - unbearable, intolerable

• च (ca) - and, also, moreover

• देवैः (devaiḥ) - by the gods

• अपि (api) - even, also, too

• सवासवैः (savāsavaiḥ) - with Vasava (Indra), including Indra

Words meanings and morphology

यदा (yadā) - when, whenever

(indeclinable)

अजानीत (ajānīta) - he knew, he recognized, he realized

(verb)

3rd person , singular, middle, imperfect (laṅ) of ā-jñā

Imperfect Middle

Imperfect tense, 3rd person singular, middle voice of ā-√jñā.

Prefix: ā

Root: jñā (class 9)

ताम् (tām) - that (feminine)

(pronoun)

Accusative, feminine, singular of tad

tad - that, this

शक्तिम् (śaktim) - the divine weapon (śakti) (power, strength, divine energy, weapon)

(noun)

Accusative, feminine, singular of śakti

śakti - power, strength, ability, faculty, divine energy, weapon (especially a spear or dart)

Root: śak (class 5)

एकघ्नीम् (ekaghnīm) - that specific weapon that can kill only one target (Indra's spear) (one-killing, slaying one (target))

(adjective)

Accusative, feminine, singular of ekaghnī

ekaghnī - one-killing, capable of slaying only one person/target

Compound of eka (one) and ghna (killing).

Compound type : tatpurusha (eka+ghna)

• eka – one, single, unique
  numeral (masculine)
• ghna – killing, destroying, slayer
  adjective (masculine)
  Derived from √han (to strike, kill).
  Root: han (class 2)

सततम् (satatam) - constantly, always, perpetually

(indeclinable)

रणे (raṇe) - in battle, in war

(noun)

Locative, masculine, singular of raṇa

raṇa - battle, fight, war, conflict

Root: raṇ (class 1)

अनिवार्याम् (anivāryām) - irresistible, unavoidable, unpreventable

(adjective)

Accusative, feminine, singular of anivārya

anivārya - irresistible, unpreventable, unavoidable

Gerundive

Negative compound of nivārya (to be prevented), derived from ni-√vṛ (to prevent).

Prefix: a

Root: vṛ (class 5)

असहाम् (asahām) - unbearable, intolerable

(adjective)

Accusative, feminine, singular of asaha

asaha - unbearable, intolerable, unable to bear

Negative compound of saha (bearing, tolerating), derived from √sah (to bear, endure).

Prefix: a

Root: sah (class 1)

च (ca) - and, also, moreover

(indeclinable)

देवैः (devaiḥ) - by the gods

(noun)

Instrumental, masculine, plural of deva

deva - god, deity, divine being

Root: div (class 4)

अपि (api) - even, also, too

(indeclinable)

सवासवैः (savāsavaiḥ) - with Vasava (Indra), including Indra

(adjective)

Instrumental, masculine, plural of savāsava

savāsava - with Vasava, accompanied by Vasava (Indra)

Bahuvrihi compound 'having Vasava (Indra) with them'.

Compound type : bahuvrihi (sa+vāsava)

• sa – with, together with
  indeclinable
• vāsava – Indra (as chief of the Vasus)
  proper noun (masculine)