महाभारतः mahābhārataḥ - book-5, chapter-47, verse-31

वृद्धौ विराटद्रुपदौ महारथौ पृथक्चमूभ्यामभिवर्तमानौ ।
यदा द्रष्टारौ धार्तराष्ट्रान्ससैन्यांस्तदा युद्धं धार्तराष्ट्रोऽन्वतप्स्यत् ॥३१॥

31. vṛddhau virāṭadrupadau mahārathau; pṛthakcamūbhyāmabhivartamānau ,
yadā draṣṭārau dhārtarāṣṭrānsasainyāṁ;stadā yuddhaṁ dhārtarāṣṭro'nvatapsyat.

31. vṛddhau virāṭadrupadau mahārathau
pṛthak camūbhyām abhivartamānau yadā
draṣṭārau dhārtarāṣṭrān sasainyān
tadā yuddham dhārtarāṣṭraḥ anvatapsyat

31. When the two elderly great charioteers, Virāṭa and Drupada, advancing with their separate armies, would see Dhṛtarāṣṭra's sons along with their forces, then Dhṛtarāṣṭra would lament the war.

Words meanings summery:

• वृद्धौ (vṛddhau) - the two old ones, elderly

• विराटद्रुपदौ (virāṭadrupadau) - Virāṭa and Drupada

• महारथौ (mahārathau) - the two great charioteers

• पृथक् (pṛthak) - separately, individually

• चमूभ्याम् (camūbhyām) - with (two) armies

• अभिवर्तमानौ (abhivartamānau) - approaching, advancing

• यदा (yadā) - when

• द्रष्टारौ (draṣṭārau) - would see (two persons), the two seers

• धार्तराष्ट्रान् (dhārtarāṣṭrān) - the Kauravas (the sons of Dhṛtarāṣṭra)

• ससैन्यान् (sasainyān) - with their armies

• तदा (tadā) - then

• युद्धम् (yuddham) - the war, battle

• धार्तराष्ट्रः (dhārtarāṣṭraḥ) - Dhṛtarāṣṭra (the king, father of the Kauravas) (Dhṛtarāṣṭra (son of Dhṛtarāṣṭra))

• अन्वतप्स्यत् (anvatapsyat) - would lament, would regret

Words meanings and morphology

वृद्धौ (vṛddhau) - the two old ones, elderly

(adjective)

Nominative, masculine, dual of vṛddha

vṛddha - old, aged, grown

Past Passive Participle

from root vṛdh

Root: vṛdh (class 1)

Note: Modifies Virāṭa and Drupada.

विराटद्रुपदौ (virāṭadrupadau) - Virāṭa and Drupada

(proper noun)

Nominative, masculine, dual of virāṭadrupada

virāṭadrupada - Virāṭa and Drupada

Compound type : dvandva (virāṭa+drupada)

• virāṭa – Virāṭa (king of Matsyas)
  proper noun (masculine)
• drupada – Drupada (king of Pañcālas)
  proper noun (masculine)

Note: Subject of the 'yadā' clause.

महारथौ (mahārathau) - the two great charioteers

(noun)

Nominative, masculine, dual of mahāratha

mahāratha - great charioteer, a warrior who can fight alone against 10,000 archers

Compound type : karmadhāraya (mahā+ratha)

• mahā – great, mighty
  adjective (masculine)
• ratha – chariot, warrior in a chariot
  noun (masculine)

Note: Apposition to Virāṭa and Drupada.

पृथक् (pṛthak) - separately, individually

(indeclinable)

Note: Modifies 'abhivartamānau' in relation to 'camūbhyām'.

चमूभ्याम् (camūbhyām) - with (two) armies

(noun)

Instrumental, feminine, dual of camū

camū - army, host

Note: Indicates the means by which they are approaching.

अभिवर्तमानौ (abhivartamānau) - approaching, advancing

(adjective)

Nominative, masculine, dual of abhivartamāna

abhivartamāna - approaching, advancing, moving towards

present middle participle

from root vṛt with prefix abhi

Prefix: abhi

Root: vṛt (class 1)

Note: Modifies Virāṭa and Drupada.

यदा (yadā) - when

(indeclinable)

द्रष्टारौ (draṣṭārau) - would see (two persons), the two seers

(noun)

Nominative, masculine, dual of draṣṭṛ

draṣṭṛ - seer, observer

agent noun

from root dṛś

Root: dṛś (class 1)

Note: Subject of the 'yadā' clause, referring to Virāṭa and Drupada.

धार्तराष्ट्रान् (dhārtarāṣṭrān) - the Kauravas (the sons of Dhṛtarāṣṭra)

(proper noun)

Accusative, masculine, plural of dhārtarāṣṭra

dhārtarāṣṭra - son of Dhṛtarāṣṭra

patronymic from Dhṛtarāṣṭra

Note: Object of 'draṣṭārau'.

ससैन्यान् (sasainyān) - with their armies

(adjective)

Accusative, masculine, plural of sasainya

sasainya - accompanied by an army, with an army

Compound type : bahuvrīhi (sa+sainya)

• sa – with, accompanied by
  indeclinable
• sainya – army
  noun (neuter)

Note: Modifies 'dhārtarāṣṭrān'.

तदा (tadā) - then

(indeclinable)

युद्धम् (yuddham) - the war, battle

(noun)

Accusative, neuter, singular of yuddha

yuddha - war, battle, fight

Past Passive Participle (used substantively)

from root yudh

Root: yudh (class 4)

Note: Object of 'anvatapsyat'.

धार्तराष्ट्रः (dhārtarāṣṭraḥ) - Dhṛtarāṣṭra (the king, father of the Kauravas) (Dhṛtarāṣṭra (son of Dhṛtarāṣṭra))

(proper noun)

Nominative, masculine, singular of dhārtarāṣṭra

dhārtarāṣṭra - son of Dhṛtarāṣṭra, belonging to Dhṛtarāṣṭra

patronymic from Dhṛtarāṣṭra

Note: Subject of 'anvatapsyat'.

अन्वतप्स्यत् (anvatapsyat) - would lament, would regret

(verb)

3rd person , singular, active, past imperfect (laṅ) of anutap

from root tap with prefix anu

Prefix: anu

Root: tap (class 1)

Note: Often used in conditional 'yada...tada' clauses to indicate 'would' or 'then'.