योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-43, verse-16

रूपालोकमनस्कारमृगतृष्णाम्बुपायिनः ।
व्यर्थमायासमायूंषि मा मा क्षपयतैणकाः ॥ १६ ॥

rūpālokamanaskāramṛgatṛṣṇāmbupāyinaḥ ,
vyarthamāyāsamāyūṃṣi mā mā kṣapayataiṇakāḥ 16

16. rūpālokamanaskāramṛgatṛṣṇāmbupāyinaḥ vyartham
āyāsam āyūṃṣi mā mā kṣapayata aiṇakāḥ

16. aiṇakāḥ rūpālokamanaskāramṛgatṛṣṇāmbupāyinaḥ
vyartham āyāsam āyūṃṣi mā mā kṣapayata

16. O deer, do not, do not waste your lives in futile striving, you who drink the water of a mirage, deluded by the mental impressions arising from the perception of forms.

Words meanings summery:

• रूपालोकमनस्कारमृगतृष्णाम्बुपायिनः (rūpālokamanaskāramṛgatṛṣṇāmbupāyinaḥ) - you who drink the water of a mirage, deluded by the mental impressions arising from the perception of forms (those who drink the water of a mirage caused by mental attention to the perception of forms)

• व्यर्थम् (vyartham) - in futile (striving) (in vain, uselessly, futilely)

• आयासम् (āyāsam) - striving (effort, exertion, trouble, striving)

• आयूंषि (āyūṁṣi) - your lives (lives, lifespans, durations of life)

• मा (mā) - do not (do not (prohibitive particle))

• मा (mā) - do not (do not (prohibitive particle))

• क्षपयत (kṣapayata) - waste (waste, spend, consume, destroy)

• ऐणकाः (aiṇakāḥ) - O deer (O deer, O fawns)

Words meanings and morphology

रूपालोकमनस्कारमृगतृष्णाम्बुपायिनः (rūpālokamanaskāramṛgatṛṣṇāmbupāyinaḥ) - you who drink the water of a mirage, deluded by the mental impressions arising from the perception of forms (those who drink the water of a mirage caused by mental attention to the perception of forms)

(noun)

Nominative, masculine, plural of rūpālokamanaskāramṛgatṛṣṇāmbupāyin

rūpālokamanaskāramṛgatṛṣṇāmbupāyin - one who drinks the water of the mirage of mental impressions from seeing forms

Compound type : tatpuruṣa (rūpa+āloka+manaskāra+mṛgatṛṣṇā+ambu+pāyin)

• rūpa – form, appearance, shape
  noun (neuter)
• āloka – seeing, perception, vision
  noun (masculine)
  Prefix: ā
  Root: lok (class 1)
• manaskāra – attention, mental impression, mental action
  noun (masculine)
  Prefix: manas
  Root: kṛ (class 8)
• mṛgatṛṣṇā – mirage (lit. deer's thirst)
  noun (feminine)
• ambu – water
  noun (neuter)
• pāyin – drinker, one who drinks
  noun (masculine)
  Agent Noun / Active Participle
  Derived from root pā (to drink) with suffix -in
  Root: pā (class 1)

व्यर्थम् (vyartham) - in futile (striving) (in vain, uselessly, futilely)

(indeclinable)

Note: Used adverbially here. Can also be accusative singular neuter.

आयासम् (āyāsam) - striving (effort, exertion, trouble, striving)

(noun)

Accusative, masculine, singular of āyāsa

āyāsa - effort, exertion, trouble, striving

Prefix: ā

Root: yas (class 4)

Note: Functions as an adverbial accusative describing the manner of wasting lives.

आयूंषि (āyūṁṣi) - your lives (lives, lifespans, durations of life)

(noun)

Accusative, neuter, plural of āyus

āyus - life, vitality, lifespan, duration of life

Note: Direct object of 'kṣapayata' (waste).

मा (mā) - do not (do not (prohibitive particle))

(indeclinable)

Note: Repeated for emphasis.

मा (mā) - do not (do not (prohibitive particle))

(indeclinable)

Note: Repeated for emphasis.

क्षपयत (kṣapayata) - waste (waste, spend, consume, destroy)

(verb)

2nd person , plural, active, imperative (loṭ) of kṣap

Causal of root kṣi (to destroy) or root kṣap (to spend)

Root: kṣap (class 10)

ऐणकाः (aiṇakāḥ) - O deer (O deer, O fawns)

(noun)

Vocative, masculine, plural of aiṇaka

aiṇaka - a small deer, a fawn