महाभारतः mahābhārataḥ - book-14, chapter-45, verse-19

नित्ययज्ञोपवीती स्याच्छुक्लवासाः शुचिव्रतः ।
नियतो दमदानाभ्यां सदा शिष्टैश्च संविशेत् ॥१९॥

19. nityayajñopavītī syācchuklavāsāḥ śucivrataḥ ,
niyato damadānābhyāṁ sadā śiṣṭaiśca saṁviśet.

19. nityayajñopavītī syāt śuklavāsāḥ śucivrataḥ
niyataḥ damadānābhyām sadā śiṣṭaiḥ ca saṃviśet

19. nityayajñopavītī syāt śuklavāsāḥ śucivrataḥ
niyataḥ damadānābhyām sadā śiṣṭaiḥ ca saṃviśet

19. One should always wear the sacred thread, be clad in white garments, and maintain pure vows. He should be self-controlled through restraint and generosity (dāna), and always associate with cultured individuals.

Words meanings summery:

• नित्ययज्ञोपवीती (nityayajñopavītī) - one who always wears the sacred thread

• स्यात् (syāt) - he should be

• शुक्लवासाः (śuklavāsāḥ) - clad in white garments

• शुचिव्रतः (śucivrataḥ) - of pure vows/observances

• नियतः (niyataḥ) - restrained, controlled, disciplined

• दमदानाभ्याम् (damadānābhyām) - by self-control and charity/donation

• सदा (sadā) - always, ever

• शिष्टैः (śiṣṭaiḥ) - with the disciplined/cultured ones

• च (ca) - and

• संविशेत् (saṁviśet) - he should associate/dwell

Words meanings and morphology

नित्ययज्ञोपवीती (nityayajñopavītī) - one who always wears the sacred thread

(adjective)

Nominative, masculine, singular of nityayajñopavītin

nityayajñopavītin - one who constantly wears the sacred thread

Compound type : tatpuruṣa (nitya+yajñopavītin)

• nitya – constant, eternal, daily, always
  adjective (masculine)
• yajñopavītin – one who wears the sacred thread
  adjective (masculine)

स्यात् (syāt) - he should be

(verb)

3rd person , singular, active, optative (vidhiliṅ) of as

Root: as (class 2)

शुक्लवासाः (śuklavāsāḥ) - clad in white garments

(adjective)

Nominative, masculine, singular of śuklavāsas

śuklavāsas - clad in white garments, wearing white clothes

Compound type : bahuvrīhi (śukla+vāsas)

• śukla – white, bright, pure
  adjective (masculine)
• vāsas – garment, clothing, cloth
  noun (neuter)

शुचिव्रतः (śucivrataḥ) - of pure vows/observances

(adjective)

Nominative, masculine, singular of śucivrata

śucivrata - of pure vows, pure in conduct or observance

Compound type : bahuvrīhi (śuci+vrata)

• śuci – pure, clean, unsullied
  adjective (masculine)
• vrata – vow, observance, religious practice, rule of conduct
  noun (neuter)

नियतः (niyataḥ) - restrained, controlled, disciplined

(adjective)

Nominative, masculine, singular of niyata

niyata - restrained, controlled, fixed, disciplined

Past Passive Participle

From root yam (to restrain) with prefix ni

Prefix: ni

Root: yam (class 1)

दमदानाभ्याम् (damadānābhyām) - by self-control and charity/donation

(noun)

Instrumental, dual of damadāna

damadāna - self-control and charity/donation

Compound type : dvandva (dama+dāna)

• dama – self-control, restraint, subduing
  noun (masculine)
• dāna – giving, gift, charity (dāna)
  noun (neuter)
  Root: dā (class 3)

सदा (sadā) - always, ever

(indeclinable)

शिष्टैः (śiṣṭaiḥ) - with the disciplined/cultured ones

(adjective)

Instrumental, masculine, plural of śiṣṭa

śiṣṭa - disciplined, cultured, taught, respectable, venerable

Past Passive Participle

From root śiṣ (to instruct, discipline)

Root: śiṣ (class 7)

च (ca) - and

(indeclinable)

संविशेत् (saṁviśet) - he should associate/dwell

(verb)

3rd person , singular, active, optative (vidhiliṅ) of saṃviś

Prefix: sam

Root: viś (class 6)