महाभारतः mahābhārataḥ - book-7, chapter-18, verse-12

आत्मनः प्रतिरूपैस्तैर्नानारूपैर्विमोहिताः ।
अन्योन्यमर्जुनं मत्वा स्वमात्मानं च जघ्निरे ॥१२॥

12. ātmanaḥ pratirūpaistairnānārūpairvimohitāḥ ,
anyonyamarjunaṁ matvā svamātmānaṁ ca jaghnire.

12. ātmanaḥ pratirūpaiḥ taiḥ nānārūpaiḥ vimohitāḥ
anyonyam arjunam matvā svam ātmānam ca jaghnire

12. taiḥ nānārūpaiḥ ātmanaḥ pratirūpaiḥ vimohitāḥ
anyonyam ca svam ātmānam arjunam matvā jaghnire

12. Bewildered by those manifold forms, which were reflections of their own selves (ātman), they, thinking each other and even their own selves (ātman) to be Arjuna, killed one another.

Words meanings summery:

• आत्मनः (ātmanaḥ) - of their own selves (ātman) (of the self, of oneself)

• प्रतिरूपैः (pratirūpaiḥ) - by reflections (by counter-forms, by reflections, by images)

• तैः (taiḥ) - by those

• नानारूपैः (nānārūpaiḥ) - by manifold forms (by various forms, by diverse forms)

• विमोहिताः (vimohitāḥ) - bewildered (deluded, bewildered, confused)

• अन्योन्यम् (anyonyam) - each other (each other, one another)

• अर्जुनम् (arjunam) - Arjuna (Arjuna (accusative))

• मत्वा (matvā) - thinking, believing (having thought, believing, considering)

• स्वम् (svam) - their own (own, one's own)

• आत्मानम् (ātmānam) - their own selves (ātman) (the self, the soul (accusative singular of ātman))

• च (ca) - and (and, also)

• जघ्निरे (jaghnire) - killed (one another) (they killed, they struck)

Words meanings and morphology

आत्मनः (ātmanaḥ) - of their own selves (ātman) (of the self, of oneself)

(noun)

Genitive, masculine, singular of ātman

ātman - self, soul, spirit, individual essence, vital breath (ātman)

Root: an (class 2)

Note: Possessive, modifies pratirūpaiḥ.

प्रतिरूपैः (pratirūpaiḥ) - by reflections (by counter-forms, by reflections, by images)

(noun)

Instrumental, neuter, plural of pratirūpa

pratirūpa - image, reflection, resemblance, counterpart

prati (against, resembling) + rūpa (form).

Compound type : tatpuruṣa (prati+rūpa)

• prati – against, towards, in return, resembling
  indeclinable
• rūpa – form, shape, image, appearance
  noun (neuter)

Note: Instrumental plural.

तैः (taiḥ) - by those

(pronoun)

Instrumental, masculine, plural of tad

tad - that, those (demonstrative pronoun)

Demonstrative pronoun stem.

Note: Instrumental plural, refers to the forms.

नानारूपैः (nānārūpaiḥ) - by manifold forms (by various forms, by diverse forms)

(adjective)

Instrumental, neuter, plural of nānārūpa

nānārūpa - having various forms/shapes; manifold

Compound of nānā (various) + rūpa (form).

Compound type : bahuvrīhi (nānā+rūpa)

• nānā – various, diverse, manifold, many
  indeclinable
• rūpa – form, shape, image, appearance
  noun (neuter)

Note: Agrees with pratirūpaiḥ.

विमोहिताः (vimohitāḥ) - bewildered (deluded, bewildered, confused)

(adjective)

Nominative, masculine, plural of vimohita

vimohita - deluded, bewildered, confused

Past Passive Participle

Formed from vi (prefix) + root muh (to be bewildered) with kta suffix.

Prefix: vi

Root: muh (class 4)

Note: Describes the implied subject (the enemies).

अन्योन्यम् (anyonyam) - each other (each other, one another)

(pronoun)

Accusative, plural of anyonyam

anyonyam - each other, one another (reciprocal pronoun/adverb)

From anya + anya.

Note: Object of matvā and jaghnire.

अर्जुनम् (arjunam) - Arjuna (Arjuna (accusative))

(proper noun)

Accusative, masculine, singular of arjuna

arjuna - Arjuna; white, silver-colored

Note: Object of matvā.

मत्वा (matvā) - thinking, believing (having thought, believing, considering)

(indeclinable)

absolutive

Formed from root man with suffix -tvā.

Root: man (class 4)

Note: Precedes jaghnire.

स्वम् (svam) - their own (own, one's own)

(pronoun)

Accusative, masculine, singular of sva

sva - own, one's own; self; property, wealth

Reflexive possessive pronoun.

Note: Agrees with ātmānam.

आत्मानम् (ātmānam) - their own selves (ātman) (the self, the soul (accusative singular of ātman))

(noun)

Accusative, masculine, singular of ātman

ātman - self, soul, spirit, individual essence, vital breath (ātman)

Root: an (class 2)

Note: Object of matvā.

च (ca) - and (and, also)

(indeclinable)

Note: Connects anyonyam and svam ātmānam.

जघ्निरे (jaghnire) - killed (one another) (they killed, they struck)

(verb)

3rd person , plural, middle, perfect (lit) of han

Root han. Perfect tense, 3rd person plural, middle voice (ātmanepada).

Root: han (class 2)

Note: The implied subject is the enemies.