महाभारतः mahābhārataḥ - book-7, chapter-163, verse-27

यदा द्रोणो न शक्नोति पाण्डवस्य विशेषणे ।
ततः प्रादुश्चकारास्त्रमस्त्रमार्गविशारदः ॥२७॥

27. yadā droṇo na śaknoti pāṇḍavasya viśeṣaṇe ,
tataḥ prāduścakārāstramastramārgaviśāradaḥ.

27. yadā droṇaḥ na śaknoti pāṇḍavasya viśeṣaṇe
tataḥ prāduḥ cakāra astram astramārgaviśāradaḥ

27. yadā droṇaḥ pāṇḍavasya viśeṣaṇe na śaknoti
tataḥ astramārgaviśāradaḥ astram prāduḥ cakāra

27. When Drona was unable to overcome the Pandava (Arjuna), then that master of weapon-craft manifested a weapon.

Words meanings summery:

• यदा (yadā) - when, at which time

• द्रोणः (droṇaḥ) - Drona

• न (na) - not, no

• शक्नोति (śaknoti) - is able, can

• पाण्डवस्य (pāṇḍavasya) - of the son of Pandu, of Arjuna

• विशेषणे (viśeṣaṇe) - in prevailing over or defeating (in distinguishing, in excelling, in overcoming)

• ततः (tataḥ) - then, therefrom

• प्रादुः (prāduḥ) - manifest, evident

• चकार (cakāra) - manifested (did, made, created)

• अस्त्रम् (astram) - a missile, a weapon

• अस्त्रमार्गविशारदः (astramārgaviśāradaḥ) - expert in the path of weapons, master of weapon-craft

Words meanings and morphology

यदा (yadā) - when, at which time

(indeclinable)

द्रोणः (droṇaḥ) - Drona

(proper noun)

Nominative, masculine, singular of droṇa

droṇa - Drona (name of a preceptor)

न (na) - not, no

(indeclinable)

शक्नोति (śaknoti) - is able, can

(verb)

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

present indicative, 5th class (śak-)

Root: śak (class 5)

पाण्डवस्य (pāṇḍavasya) - of the son of Pandu, of Arjuna

(noun)

Genitive, masculine, singular of pāṇḍava

pāṇḍava - a descendant of Pāṇḍu, Arjuna

derived from Pāṇḍu

विशेषणे (viśeṣaṇe) - in prevailing over or defeating (in distinguishing, in excelling, in overcoming)

(noun)

Locative, neuter, singular of viśeṣaṇa

viśeṣaṇa - distinction, differentiating, specification, excelling

verbal noun

from vi-śiṣ (to distinguish)

Prefix: vi

Root: śiṣ (class 7)

ततः (tataḥ) - then, therefrom

(indeclinable)

प्रादुः (prāduḥ) - manifest, evident

(indeclinable)

चकार (cakāra) - manifested (did, made, created)

(verb)

3rd person , singular, active, perfect (lit) of kṛ

perfect tense, 3rd person singular

Root: kṛ (class 8)

अस्त्रम् (astram) - a missile, a weapon

(noun)

Accusative, neuter, singular of astra

astra - a missile, a weapon (especially a magical or divine one)

अस्त्रमार्गविशारदः (astramārgaviśāradaḥ) - expert in the path of weapons, master of weapon-craft

(adjective)

Nominative, masculine, singular of astramārgaviśārada

astramārgaviśārada - expert in the path/science of weapons

Compound type : tatpuruṣa (astra+mārga+viśārada)

• astra – weapon, missile
  noun (neuter)
• mārga – path, way, course
  noun (masculine)
• viśārada – expert, skilled, proficient
  adjective (masculine)