महाभारतः mahābhārataḥ - book-8, chapter-66, verse-48

बलेनाथ स संस्तभ्य ब्रह्मास्त्रं समुदैरयत् ।
ऐन्द्रास्त्रमर्जुनश्चापि तद्दृष्ट्वाभिन्यमन्त्रयत् ॥४८॥

48. balenātha sa saṁstabhya brahmāstraṁ samudairayat ,
aindrāstramarjunaścāpi taddṛṣṭvābhinyamantrayat.

48. balena atha saḥ saṃstabhya brahmāstram samudairayat
aindrāstram arjunaḥ ca api tat dṛṣṭvā abhinyamantrayat

48. atha saḥ balena saṃstabhya brahmāstram samudairayat ca
api arjunaḥ tat dṛṣṭvā aindrāstram abhinyamantrayat

48. Then, having stabilized himself with (his) inner strength, he (Karna) discharged the Brahmastra (divine weapon). And Arjuna, having seen that (Brahmastra), also invoked the Aindrāstra (divine weapon).

Words meanings summery:

• बलेन (balena) - by his (Karna's) inner strength or martial power (by force, with strength)

• अथ (atha) - then, indicating sequence of events (then, now, moreover)

• सः (saḥ) - he (Karna) (he, that)

• संस्तभ्य (saṁstabhya) - having stabilized himself, having gathered his resolve (having supported, having checked, having stabilized, having composed oneself)

• ब्रह्मास्त्रम् (brahmāstram) - a powerful celestial weapon (astra) associated with Brahma (Brahmastra (divine weapon))

• समुदैरयत् (samudairayat) - he (Karna) discharged the Brahmastra (he/she/it discharged, sent forth, hurled)

• ऐन्द्रास्त्रम् (aindrāstram) - a powerful celestial weapon (astra) associated with Indra (Aindrāstra (divine weapon of Indra))

• अर्जुनः (arjunaḥ) - Arjuna, one of the Pandava brothers (Arjuna (proper noun))

• च (ca) - and, connecting Arjuna's action to Karna's (and, also)

• अपि (api) - also, implying a reciprocal action (also, even, too)

• तत् (tat) - that (Brahmastra discharged by Karna) (that)

• दृष्ट्वा (dṛṣṭvā) - having seen the Brahmastra being discharged (having seen)

• अभिन्यमन्त्रयत् (abhinyamantrayat) - he (Arjuna) invoked (the Aindrāstra) with proper mantras (he/she/it invoked, consecrated, muttered incantations)

Words meanings and morphology

बलेन (balena) - by his (Karna's) inner strength or martial power (by force, with strength)

(noun)

Instrumental, neuter, singular of bala

bala - strength, power, force, army

अथ (atha) - then, indicating sequence of events (then, now, moreover)

(indeclinable)

सः (saḥ) - he (Karna) (he, that)

(pronoun)

Nominative, masculine, singular of tad

tad - that, he, she, it

Note: Refers to Karna.

संस्तभ्य (saṁstabhya) - having stabilized himself, having gathered his resolve (having supported, having checked, having stabilized, having composed oneself)

(indeclinable)

absolutive (gerund)

root stambh with prefix sam + suffix -ya

Prefix: sam

Root: stambh (class 5)

ब्रह्मास्त्रम् (brahmāstram) - a powerful celestial weapon (astra) associated with Brahma (Brahmastra (divine weapon))

(noun)

Accusative, neuter, singular of brahmāstra

brahmāstra - the weapon (astra) of Brahmā, a powerful divine missile

Compound type : tatpuruṣa (brahman+astra)

• brahman – Brahma (the creator deity); the absolute reality (brahman)
  proper noun (masculine)
• astra – missile, projectile, weapon
  noun (neuter)
  Root: as (class 4)

Note: Object of samudairayat.

समुदैरयत् (samudairayat) - he (Karna) discharged the Brahmastra (he/she/it discharged, sent forth, hurled)

(verb)

3rd person , singular, active, past imperfect (laṅ) of sam-ud-īr

causative imperfect 3rd person singular active

Causative stem from root īr with prefixes sam and ud

Prefixes: sam+ud

Root: īr (class 2)

ऐन्द्रास्त्रम् (aindrāstram) - a powerful celestial weapon (astra) associated with Indra (Aindrāstra (divine weapon of Indra))

(noun)

Accusative, neuter, singular of aindrāstra

aindrāstra - the weapon (astra) of Indra, a powerful divine missile

derived from Indra + astra

Compound type : tatpuruṣa (indra+astra)

• indra – Indra (name of a deity)
  proper noun (masculine)
• astra – missile, projectile, weapon
  noun (neuter)
  Root: as (class 4)

Note: Object of abhinyamantrayat.

अर्जुनः (arjunaḥ) - Arjuna, one of the Pandava brothers (Arjuna (proper noun))

(proper noun)

Nominative, masculine, singular of arjuna

arjuna - Arjuna (proper noun), white, clear, silver

Note: Subject of abhinyamantrayat.

च (ca) - and, connecting Arjuna's action to Karna's (and, also)

(indeclinable)

अपि (api) - also, implying a reciprocal action (also, even, too)

(indeclinable)

तत् (tat) - that (Brahmastra discharged by Karna) (that)

(pronoun)

Accusative, neuter, singular of tad

tad - that, he, she, it

Note: Object of dṛṣṭvā.

दृष्ट्वा (dṛṣṭvā) - having seen the Brahmastra being discharged (having seen)

(indeclinable)

absolutive (gerund)

root dṛś + suffix -tvā

Root: dṛś (class 1)

अभिन्यमन्त्रयत् (abhinyamantrayat) - he (Arjuna) invoked (the Aindrāstra) with proper mantras (he/she/it invoked, consecrated, muttered incantations)

(verb)

3rd person , singular, active, past imperfect (laṅ) of abhi-ni-mantr

imperfect 3rd person singular active

Stem mantraya from root mantr with prefixes abhi and ni, 10th class

Prefixes: abhi+nis

Root: mantr (class 10)