योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-67, verse-33

दुःसाध्याः सिद्धिमायान्ति रिपवो यान्ति मित्रताम् ।
विषाण्यमृततां यान्ति संतताभ्यासयोगतः ॥ ३३ ॥

duḥsādhyāḥ siddhimāyānti ripavo yānti mitratām ,
viṣāṇyamṛtatāṃ yānti saṃtatābhyāsayogataḥ 33

33. duḥsādhyāḥ siddhim āyānti ripavaḥ yānti mitratām
viṣāṇi amṛtatām yānti santatābhyāsayogataḥ

33. santatābhyāsayogataḥ duḥsādhyāḥ siddhim āyānti
ripavaḥ mitratām yānti viṣāṇi amṛtatām yānti

33. Difficult endeavors achieve success (siddhi), enemies become friends, and poisons transform into nectar, all through the discipline (yoga) of continuous practice (abhyāsa).

Words meanings summery:

• दुःसाध्याः (duḥsādhyāḥ) - difficult endeavors/tasks (difficult to accomplish, hard to achieve, formidable)

• सिद्धिम् (siddhim) - success, accomplishment, perfection, supernatural power (siddhi)

• आयान्ति (āyānti) - they achieve, they acquire (they come, they attain, they approach)

• रिपवः (ripavaḥ) - enemies, foes

• मित्रताम् (mitratām) - friendship, friendliness, alliance

• विषाणि (viṣāṇi) - poisons, venom

• अमृतताम् (amṛtatām) - nectar, the state of being immortal (immortality, nectar-like quality)

• सन्तताभ्यासयोगतः (santatābhyāsayogataḥ) - through the discipline of continuous practice

Words meanings and morphology

दुःसाध्याः (duḥsādhyāḥ) - difficult endeavors/tasks (difficult to accomplish, hard to achieve, formidable)

(adjective)

Nominative, masculine, plural of duḥsādhya

duḥsādhya - difficult to accomplish, hard to achieve, formidable, intractable

Gerundive

Compound of duḥ (hard, bad) and sādhya (to be accomplished).

Compound type : avyayībhāva (duḥ+sādhya)

• duḥ – bad, hard, difficult, ill
  indeclinable
  Prefix indicating difficulty or badness.
• sādhya – to be accomplished, achievable, practicable
  adjective
  Gerundive
  Derived from root sādh (to accomplish, effect) with suffix -ya.
  Root: sādh (class 5)

Note: Can be interpreted as 'difficult tasks' (noun by ellipsis).

सिद्धिम् (siddhim) - success, accomplishment, perfection, supernatural power (siddhi)

(noun)

Accusative, feminine, singular of siddhi

siddhi - success (siddhi), accomplishment, perfection, supernatural power

Noun derived from verb

From root sidh (to succeed, accomplish).

Root: sidh (class 1)

आयान्ति (āyānti) - they achieve, they acquire (they come, they attain, they approach)

(verb)

3rd person , plural, active, present (lat) of āyā

Root yā (to go) with prefix ā. Present, 3rd person, plural, active.

Prefix: ā

Root: yā (class 2)

रिपवः (ripavaḥ) - enemies, foes

(noun)

Nominative, masculine, plural of ripu

ripu - enemy, foe, rival

U-stem noun.

मित्रताम् (mitratām) - friendship, friendliness, alliance

(noun)

Accusative, feminine, singular of mitratā

mitratā - friendship, friendliness, alliance

Derived from mitra (friend) with suffix -tā.

विषाणि (viṣāṇi) - poisons, venom

(noun)

Nominative, neuter, plural of viṣa

viṣa - poison, venom, bane

अमृतताम् (amṛtatām) - nectar, the state of being immortal (immortality, nectar-like quality)

(noun)

Accusative, feminine, singular of amṛtatā

amṛtatā - immortality, nectar-like quality, deathlessness

Derived from amṛta (immortal, nectar) with suffix -tā.

सन्तताभ्यासयोगतः (santatābhyāsayogataḥ) - through the discipline of continuous practice

(noun)

Ablative, masculine, singular of santatābhyāsayoga

santatābhyāsayoga - discipline (yoga) of continuous practice (abhyāsa)

Compound of santata, abhyāsa, and yoga.

Compound type : tatpuruṣa (santata+abhyāsa+yoga)

• santata – continuous, unbroken, constant
  adjective
  Past Passive Participle
  Derived from root tan (to stretch, extend) with prefix sam.
  Prefix: sam
  Root: tan (class 8)
• abhyāsa – practice (abhyāsa), repetition, exercise
  noun (masculine)
  Noun derived from verb
  From root as (to throw) with prefix abhi.
  Prefix: abhi
  Root: as (class 4)
• yoga – discipline (yoga), union, method, application, spiritual practice
  noun (masculine)
  Noun derived from verb
  From root yuj (to join).
  Root: yuj (class 7)

Note: Ablative suffix -taḥ indicates "from" or "through".