महाभारतः mahābhārataḥ - book-5, chapter-167, verse-9

वयोवृद्धावपि तु तौ क्षत्रधर्मपरायणौ ।
यतिष्येते परं शक्त्या स्थितौ वीरगते पथि ॥९॥

9. vayovṛddhāvapi tu tau kṣatradharmaparāyaṇau ,
yatiṣyete paraṁ śaktyā sthitau vīragate pathi.

9. vayovṛddhau api tu tau kṣatradharmaparāyaṇau
yatiṣyete param śaktyā sthitau vīragate pathi

9. tu api tau vayovṛddhau kṣatradharmaparāyaṇau
vīragate pathi sthitau param śaktyā yatiṣyete

9. Although they are aged, those two, devoted to the warrior's natural law (kṣatradharma), will strive with utmost strength, abiding on the path trodden by heroes.

Words meanings summery:

• वयोवृद्धौ (vayovṛddhau) - aged, old

• अपि (api) - although, even (also, even, too)

• तु (tu) - but, on the other hand, indeed

• तौ (tau) - those two

• क्षत्रधर्मपरायणौ (kṣatradharmaparāyaṇau) - devoted to the warrior's natural law/constitution

• यतिष्येते (yatiṣyete) - they two will strive/endeavor

• परम् (param) - with utmost (strength) (supreme, utmost, to the highest degree)

• शक्त्या (śaktyā) - by strength, with power

• स्थितौ (sthitau) - situated, abiding, standing

• वीरगते (vīragate) - on the path of heroes, on the path trodden by heroes

• पथि (pathi) - on the path

Words meanings and morphology

वयोवृद्धौ (vayovṛddhau) - aged, old

(adjective)

Nominative, masculine, dual of vayovṛddha

vayovṛddha - aged, advanced in years

Compound type : tatpuruṣa (vayas+vṛddha)

• vayas – age, period of life, youth
  noun (neuter)
• vṛddha – grown, old, aged, increased
  adjective
  Past Passive Participle
  Root: vṛdh (class 1)

अपि (api) - although, even (also, even, too)

(indeclinable)

तु (tu) - but, on the other hand, indeed

(indeclinable)

तौ (tau) - those two

(pronoun)

Nominative, masculine, dual of tad

tad - that, those

क्षत्रधर्मपरायणौ (kṣatradharmaparāyaṇau) - devoted to the warrior's natural law/constitution

(adjective)

Nominative, masculine, dual of kṣatradharmaparāyaṇa

kṣatradharmaparāyaṇa - devoted to the duty/natural law of a kṣatriya, intent on the warrior's constitution

Compound type : tatpuruṣa (kṣatradharma+parāyaṇa)

• kṣatradharma – the duty or natural law (dharma) of the warrior (kṣatra) class
  noun (masculine)
• parāyaṇa – devoted to, intent on, having as one's highest goal
  adjective

यतिष्येते (yatiṣyete) - they two will strive/endeavor

(verb)

3rd person , dual, middle, future (lṛṭ) of yat

Root: yat (class 1)

परम् (param) - with utmost (strength) (supreme, utmost, to the highest degree)

(indeclinable)

शक्त्या (śaktyā) - by strength, with power

(noun)

Instrumental, feminine, singular of śakti

śakti - power, strength, ability (śakti)

स्थितौ (sthitau) - situated, abiding, standing

(adjective)

Nominative, masculine, dual of sthita

sthita - standing, situated, abiding, firm

Past Passive Participle

Root: sthā (class 1)

वीरगते (vīragate) - on the path of heroes, on the path trodden by heroes

(adjective)

Locative, masculine, singular of vīragata

vīragata - gone by heroes, trodden by heroes

Compound type : tatpuruṣa (vīra+gata)

• vīra – hero, brave man
  noun (masculine)
• gata – gone, moved, resorted to, followed
  adjective
  Past Passive Participle
  Root: gam (class 1)

पथि (pathi) - on the path

(noun)

Locative, masculine, singular of pathin

pathin - path, road, way