महाभारतः mahābhārataḥ - book-6, chapter-90, verse-12

तदाचार्यवचः श्रुत्वा सोमदत्तपुरोगमाः ।
तावकाः समवर्तन्त पाण्डवानामनीकिनीम् ॥१२॥

12. tadācāryavacaḥ śrutvā somadattapurogamāḥ ,
tāvakāḥ samavartanta pāṇḍavānāmanīkinīm.

12. tadā ācāryavacaḥ śrutvā somadattapurogamāḥ
tāvakāḥ samavartanta pāṇḍavānām anīkinīm

12. tadā ācāryavacaḥ śrutvā somadattapurogamāḥ
tāvakāḥ pāṇḍavānām anīkinīm samavartanta

12. Then, having heard the preceptor's words, your men, with Somadatta at their head, advanced upon the Pāṇḍavas' army.

Words meanings summery:

• तदा (tadā) - then, at that time

• आचार्यवचः (ācāryavacaḥ) - referring to Droṇa's words (the preceptor's words, the guru's speech)

• श्रुत्वा (śrutvā) - having heard, after hearing

• सोमदत्तपुरोगमाः (somadattapurogamāḥ) - having Somadatta at the forefront, led by Somadatta

• तावकाः (tāvakāḥ) - referring to Duryodhana's (Dhṛtarāṣṭra's) warriors (your people, your men, your sons)

• समवर्तन्त (samavartanta) - they moved into battle against (they advanced, they turned towards, they encountered)

• पाण्डवानाम् (pāṇḍavānām) - of the Pandavas, belonging to the Pandavas

• अनीकिनीम् (anīkinīm) - army, host

Words meanings and morphology

तदा (tadā) - then, at that time

(indeclinable)

adverbial suffix dā

Root: tad

आचार्यवचः (ācāryavacaḥ) - referring to Droṇa's words (the preceptor's words, the guru's speech)

(noun)

Accusative, neuter, singular of ācāryavacas

ācāryavacas - the words of a teacher/preceptor

Compound type : tatpurusha (ācārya+vacas)

• ācārya – teacher, preceptor, guru
  noun (masculine)
• vacas – word, speech, saying
  noun (neuter)
  Root: vac (class 2)

Note: Nominative/Accusative singular of neuter s-stem, vacas. Here it acts as object of śrutvā.

श्रुत्वा (śrutvā) - having heard, after hearing

(indeclinable)

absolutive

formed with suffix ktvā

Root: śru (class 5)

सोमदत्तपुरोगमाः (somadattapurogamāḥ) - having Somadatta at the forefront, led by Somadatta

(adjective)

Nominative, masculine, plural of somadattapurogama

somadattapurogama - one who has Somadatta as leader/at the front

Compound type : bahuvrihi (somadatta+puras+gama)

• somadatta – name of a warrior; given by Soma
  proper noun (masculine)
• puras – before, in front, eastward
  indeclinable
• gama – going, moving, leading
  adjective (masculine)
  derived from root gam- to go
  Root: gam (class 1)

तावकाः (tāvakāḥ) - referring to Duryodhana's (Dhṛtarāṣṭra's) warriors (your people, your men, your sons)

(pronoun)

Nominative, masculine, plural of tāvaka

tāvaka - yours, belonging to you, your kin

derived from tvad (you) + aka

समवर्तन्त (samavartanta) - they moved into battle against (they advanced, they turned towards, they encountered)

(verb)

3rd person , plural, middle, past imperfect (laṅ) of sam-vart

imperfect 3rd plural middle voice

Prefix: sam

Root: vṛt (class 1)

Note: With sam, meaning 'to turn towards, to engage'.

पाण्डवानाम् (pāṇḍavānām) - of the Pandavas, belonging to the Pandavas

(proper noun)

Genitive, masculine, plural of pāṇḍava

pāṇḍava - descendant of Pāṇḍu, son of Pāṇḍu (Yudhiṣṭhira, Bhīma, Arjuna, Nakula, Sahadeva)

from paṇḍu + aṇ (descendant)

अनीकिनीम् (anīkinīm) - army, host

(noun)

Accusative, feminine, singular of anīkinī

anīkinī - an army, a host, a military division