महाभारतः mahābhārataḥ - book-13, chapter-149, verse-13

यदा प्रमाणप्रभवः स्वभावश्च सुखासुखे ।
मशकीटपिपीलानां स्थिरो भव युधिष्ठिर ॥१३॥

13. yadā pramāṇaprabhavaḥ svabhāvaśca sukhāsukhe ,
maśakīṭapipīlānāṁ sthiro bhava yudhiṣṭhira.

13. yadā pramāṇaprabhavaḥ svabhāvaḥ ca sukhāsukhe
maśakīṭapipīlānām sthiraḥ bhava yudhiṣṭhira

13. yudhiṣṭhira yadā maśakīṭapipīlānām pramāṇaprabhavaḥ svabhāvaḥ ca sukhāsukhe [bhavanti],
[tadā tvam] sthiraḥ bhava.

13. O Yudhiṣṭhira, be firm (in your understanding), for even the intrinsic nature (svabhāva) and the happiness and unhappiness of mosquitoes, insects, and ants arise from valid perception.

Words meanings summery:

• यदा (yadā) - for when, when (when, whenever)

• प्रमाणप्रभवः (pramāṇaprabhavaḥ) - arising from valid perception (originating from valid means of knowledge/perception, born of evidence)

• स्वभावः (svabhāvaḥ) - intrinsic nature (svabhāva) (own being, intrinsic nature, inherent disposition)

• च (ca) - and (and, also, moreover)

• सुखासुखे (sukhāsukhe) - happiness and unhappiness (happiness and unhappiness, pleasure and pain)

• मशकीटपिपीलानाम् (maśakīṭapipīlānām) - of mosquitoes, insects, and ants

• स्थिरः (sthiraḥ) - firm, steadfast (firm, steady, stable, constant)

• भव (bhava) - be (be, become, exist)

• युधिष्ठिर (yudhiṣṭhira) - O Yudhiṣṭhira (Yudhiṣṭhira (a proper name, eldest of the Pāṇḍavas))

Words meanings and morphology

यदा (yadā) - for when, when (when, whenever)

(indeclinable)

प्रमाणप्रभवः (pramāṇaprabhavaḥ) - arising from valid perception (originating from valid means of knowledge/perception, born of evidence)

(adjective)

Nominative, masculine, singular of pramāṇaprabhava

pramāṇaprabhava - originating from valid means of knowledge/perception, born of evidence

Compound type : tatpurusha (pramāṇa+prabhava)

• pramāṇa – valid means of knowledge, perception, proof, measure
  noun (neuter)
  Prefix: pra
  Root: mā (class 3)
• prabhava – origin, source, birth, power; originating from
  noun (masculine)
  Prefix: pra
  Root: bhū (class 1)

स्वभावः (svabhāvaḥ) - intrinsic nature (svabhāva) (own being, intrinsic nature, inherent disposition)

(noun)

Nominative, masculine, singular of svabhāva

svabhāva - own being, intrinsic nature, inherent disposition

Compound type : tatpurusha (sva+bhāva)

• sva – own, self
  pronoun
• bhāva – being, existence, state, nature, disposition
  noun (masculine)
  Root: bhū (class 1)

च (ca) - and (and, also, moreover)

(indeclinable)

सुखासुखे (sukhāsukhe) - happiness and unhappiness (happiness and unhappiness, pleasure and pain)

(noun)

Nominative, neuter, dual of sukhāsukha

sukhāsukha - happiness and unhappiness, pleasure and pain

Compound type : dvandva (sukha+asukha)

• sukha – happiness, pleasure, ease
  noun (neuter)
• asukha – unhappiness, pain, discomfort
  noun (neuter)

Note: Can also be accusative dual, but nominative as part of the subject is implied here.

मशकीटपिपीलानाम् (maśakīṭapipīlānām) - of mosquitoes, insects, and ants

(noun)

Genitive, masculine, plural of maśakīṭapipīla

maśakīṭapipīla - mosquito, insect, and ant (collectively)

Compound type : dvandva (maśaka+kīṭa+pipīla)

• maśaka – mosquito
  noun (masculine)
• kīṭa – insect, worm
  noun (masculine)
• pipīla – ant
  noun (masculine)

स्थिरः (sthiraḥ) - firm, steadfast (firm, steady, stable, constant)

(adjective)

Nominative, masculine, singular of sthira

sthira - firm, steady, stable, constant

Root: sthā (class 1)

भव (bhava) - be (be, become, exist)

(verb)

2nd person , singular, active, imperative (loṭ) of bhū

imperative 2nd singular

Root: bhū (class 1)

युधिष्ठिर (yudhiṣṭhira) - O Yudhiṣṭhira (Yudhiṣṭhira (a proper name, eldest of the Pāṇḍavas))

(proper noun)

Vocative, masculine, singular of yudhiṣṭhira

yudhiṣṭhira - Yudhiṣṭhira (proper name, 'firm in battle')

Compound type : tatpurusha (yudhi+sthira)

• yudhi – in battle (locative of yudh 'battle')
  noun (feminine)
  Root: yudh (class 4)
• sthira – firm, steady
  adjective (masculine)
  Root: sthā (class 1)