महाभारतः mahābhārataḥ - book-12, chapter-203, verse-12

यत्तदक्षरमव्यक्तममृतं ब्रह्म शाश्वतम् ।
वदन्ति पुरुषव्याघ्रं केशवं पुरुषर्षभम् ॥१२॥

12. yattadakṣaramavyaktamamṛtaṁ brahma śāśvatam ,
vadanti puruṣavyāghraṁ keśavaṁ puruṣarṣabham.

12. yat tat akṣaram avyaktam amṛtam brahma śāśvatam
vadanti puruṣavyāghram keśavam puruṣarṣabham

12. vadanti keśavam puruṣavyāghram puruṣarṣabham
yat tat akṣaram avyaktam amṛtam śāśvatam brahma

12. Sages declare Keśava, the foremost among men, to be that imperishable, unmanifest, immortal, and eternal supreme reality (brahman).

Words meanings summery:

• यत् (yat) - which, whatever, that which

• तत् (tat) - that, it

• अक्षरम् (akṣaram) - imperishable, indestructible, undecaying

• अव्यक्तम् (avyaktam) - unmanifested, invisible, indiscernible

• अमृतम् (amṛtam) - immortal, undying, nectar

• ब्रह्म (brahma) - Brahman, the ultimate reality, the absolute

• शाश्वतम् (śāśvatam) - eternal, perpetual, everlasting

• वदन्ति (vadanti) - they speak, they say, they declare

• पुरुषव्याघ्रम् (puruṣavyāghram) - Keśava, who is the best among men (tiger among men, best among men, excellent man)

• केशवम् (keśavam) - Keśava (an epithet of Krishna/Vishnu)

• पुरुषर्षभम् (puruṣarṣabham) - Keśava, who is the best among men (bull among men, best among men, excellent man)

Words meanings and morphology

यत् (yat) - which, whatever, that which

(pronoun)

Nominative, neuter, singular of yad

yad - which, what, whatever

तत् (tat) - that, it

(pronoun)

Nominative, neuter, singular of tad

tad - that, this, it

अक्षरम् (akṣaram) - imperishable, indestructible, undecaying

(adjective)

Nominative, neuter, singular of akṣara

akṣara - imperishable, undecaying, syllable, letter

अव्यक्तम् (avyaktam) - unmanifested, invisible, indiscernible

(adjective)

Nominative, neuter, singular of avyakta

avyakta - unmanifested, invisible, not evident

अमृतम् (amṛtam) - immortal, undying, nectar

(adjective)

Nominative, neuter, singular of amṛta

amṛta - immortal, imperishable, nectar, elixir of immortality

ब्रह्म (brahma) - Brahman, the ultimate reality, the absolute

(noun)

Nominative, neuter, singular of brahman

brahman - Brahman, the ultimate reality, the absolute, the sacred word, the Vedas

शाश्वतम् (śāśvatam) - eternal, perpetual, everlasting

(adjective)

Nominative, neuter, singular of śāśvata

śāśvata - eternal, perpetual, constant, permanent

वदन्ति (vadanti) - they speak, they say, they declare

(verb)

3rd person , plural, active, present indicative (laṭ) of vad

Root: vad (class 1)

पुरुषव्याघ्रम् (puruṣavyāghram) - Keśava, who is the best among men (tiger among men, best among men, excellent man)

(noun)

Accusative, masculine, singular of puruṣavyāghra

puruṣavyāghra - tiger among men, best of men

Compound type : Tatpuruṣa (puruṣa+vyāghra)

• puruṣa – man, person, male, human being
  noun (masculine)
• vyāghra – tiger, best, excellent one
  noun (masculine)

केशवम् (keśavam) - Keśava (an epithet of Krishna/Vishnu)

(proper noun)

Accusative, masculine, singular of keśava

keśava - Keśava (name of Vishnu/Krishna, slayer of the demon Keśī, or one with beautiful hair)

पुरुषर्षभम् (puruṣarṣabham) - Keśava, who is the best among men (bull among men, best among men, excellent man)

(noun)

Accusative, masculine, singular of puruṣarṣabha

puruṣarṣabha - bull among men, best of men

Compound type : Tatpuruṣa (puruṣa+ṛṣabha)

• puruṣa – man, person, male, human being
  noun (masculine)
• ṛṣabha – bull, chief, excellent one
  noun (masculine)