महाभारतः mahābhārataḥ - book-5, chapter-36, verse-17

नानर्थकं सान्त्वयति प्रतिज्ञाय ददाति च ।
राद्धापराद्धे जानाति यः स मध्यमपूरुषः ॥१७॥

17. nānarthakaṁ sāntvayati pratijñāya dadāti ca ,
rāddhāparāddhe jānāti yaḥ sa madhyamapūruṣaḥ.

17. na anarthakam sāntvayati pratijñāya dadāti ca
rāddhāparāddhe jānāti yaḥ sa madhyamapūruṣaḥ

17. A person who consoles appropriately and gives what he has promised, and who understands both successful and unsuccessful deeds, is considered a middling (madhyama puruṣa) individual.

Words meanings summery:

• न (na) - not, no

• अनर्थकम् (anarthakam) - uselessly, in vain, for no purpose

• सान्त्वयति (sāntvayati) - consoles, pacifies

• प्रतिज्ञाय (pratijñāya) - having promised, having undertaken

• ददाति (dadāti) - gives, grants

• च (ca) - and, also

• राद्धापराद्धे (rāddhāparāddhe) - successes and failures, things done right and wrong

• जानाति (jānāti) - knows, understands

• यः (yaḥ) - who, he who

• स (sa) - he, that

• मध्यमपूरुषः (madhyamapūruṣaḥ) - a middling person, a person of average character

Words meanings and morphology

न (na) - not, no

(indeclinable)

अनर्थकम् (anarthakam) - uselessly, in vain, for no purpose

(adjective)

Accusative, neuter, singular of anarthaka

anarthaka - useless, purposeless, meaningless

Compound type : bahuvrīhi (an+artha)

• an – not
  indeclinable
• artha – purpose, meaning, wealth, object
  noun (masculine)

Note: Functions as an adverb here.

सान्त्वयति (sāntvayati) - consoles, pacifies

(verb)

3rd person , singular, active, present (laṭ) of sāntvaya

causative/denominal

From 'sāntva' (consolation) + 'ya' suffix.

प्रतिज्ञाय (pratijñāya) - having promised, having undertaken

(indeclinable)

absolutive/gerund

Absolutive form from root 'jñā' with prefix 'prati'.

Prefix: prati

Root: jñā (class 9)

ददाति (dadāti) - gives, grants

(verb)

3rd person , singular, active, present (laṭ) of dā

Root: dā (class 3)

च (ca) - and, also

(indeclinable)

राद्धापराद्धे (rāddhāparāddhe) - successes and failures, things done right and wrong

(noun)

Accusative, neuter, dual of rāddhāparāddha

rāddhāparāddha - things achieved and things failed, right and wrong deeds

Compound type : dvandva (rāddha+aparāddha)

• rāddha – accomplished, succeeded, prospered
  verbal derivative (neuter)
  Past Passive Participle
  From root 'rādh' (to succeed, to accomplish).
  Root: rādh (class 4)
• aparāddha – failed, erred, done wrong
  verbal derivative (neuter)
  Past Passive Participle
  From root 'rādh' with prefix 'apa'.
  Prefix: apa
  Root: rādh (class 4)

Note: It can also be nominative dual, but accusative makes more sense with jānāti.

जानाति (jānāti) - knows, understands

(verb)

3rd person , singular, active, present (laṭ) of jñā

Root: jñā (class 9)

यः (yaḥ) - who, he who

(pronoun)

Nominative, masculine, singular of yad

yad - who, which, what

Note: Relative pronoun.

स (sa) - he, that

(pronoun)

Nominative, masculine, singular of tad

tad - he, she, it, that

Note: Correlative pronoun.

मध्यमपूरुषः (madhyamapūruṣaḥ) - a middling person, a person of average character

(noun)

Nominative, masculine, singular of madhyamapūruṣa

madhyamapūruṣa - a middle man, an average person, a middling character

Compound type : karmadhāraya (madhyama+puruṣa)

• madhyama – middle, average, mediocre
  adjective (masculine)
• puruṣa – man, person, male, spirit (puruṣa)
  noun (masculine)