BhG 18.49

syntax

sarvatra (everywhere) asakta-buddhiḥ (whose intelligence is not attached) jitātmā (whose self is conquered) vigata-spṛhaḥ (whose hankering is gone) saṁnyāsena (by renunciation) paramām naiṣkarmya-siddhim (the supreme perfection of freedom of activity) adhigacchati (he obtains).

grammar

asakta-buddhiḥ	–	asakta-ātman 1n.1 m.; BV: yasya buddhir asaktāsti saḥ – whose intelligence is not attached (from: √sañj – to attach, to stick, to embrace, PP a-sakta – unattached; √budh – to wake, to perceive, to understand; buddhi – intelligence, thought, understanding, knowledge, idea, opinion);
sarvatra	–	av. – everywhere, in every case (from: sarva – all; indeclinable locative with an ending –tra);
jitātmā	–	jita-ātman 1n.1 m.; BV: yasyātmā jito ‘sti saḥ – whose self is conquered (from: √ji – to conquer, PP jita – conquered, defeated; ātman – self);
vigata-spṛhaḥ	–	vigata-spṛha 1n.1 m.; BV: yasya spṛhā vigatāsti saḥ – whose hankering is gone (from: vi-√gam – to go away, PP vigata – gone; √spṛh – to desire to obtain, to long for, spṛhā – eager desire, longing);
naiṣkarmya-siddhim	–	naiṣ-karmya-siddhim 2n.1 f.; TP: naiṣkarmyasya siddhim iti – perfction of freedom from activity (from: niḥ – out of, away from, without; √kṛ – to do, karman – activity and its result; niṣ-karman – freedom from activity and its results, naiṣ-karmya – freedom from activity and its results; √sidh – to succeed, to become perfect, siddhi – success, perfection);
paramām	–	paramā 2n.1 f. – the supreme (superlative of: para – beyond, ancient, final, the best, the supreme);
saṁnyāsena	–	saṁnyāsa 3n.1 m. – by laying aside, by resignation, by renunciation (from: sam-ni-√as – to lay aside, to renounce, to give up);
adhigacchati	–	adhi-√gam (to cross over, to obtain) Praes. P 1v.1 – he obtains;

textual variants

asakta-buddhiḥ → asaktaḥ buddhiḥ / asakti-buddhiḥ (unattached, intelligence / intelligent because of the lack of attachment);
naiṣkarmya-siddhiṁ → niṣkarma-siddhiṁ / naiṣkarma-siddhiṁ / naiḥ-karmya-siddhim (perfection of inactivity);

Śāṃkara

yā karmajā siddhir uktā jñāna-niṣṭhā-yogyatā-lakṣaṇā, taryāḥ phala-bhūtā naiṣkarmya-siddhir jñāna-niṣṭhā-lakṣaṇā ca vaktavyeti śloka ārabhyate—

asakta-buddhir asaktā saṅgarahitā buddhir antaḥkaraṇaṃ yasya so’sakta-buddhiḥ sarvatra putra-dārādiṣu āsakti-nimitteṣu, jitātmā jito vaśīkṛtaḥ ātmāntaḥ-karaṇaṃ yasya sa jitātmā, vigata-spṛho vigatā spṛhā tṛṣṇā deha-jīvita-bhogeṣu yasmāt sa vigata-spṛhaḥ | ya evaṃ-bhūta ātmajñaḥ sa naiṣkarmya-siddhiṃ nirgatāni karmāṇi yasmān niṣkriya-brahmātma-sambodhāt sa niṣkarmā tasya bhāvo naiṣkarmyam | naiṣkarmyaṃ ca tat siddhiś ca sā naiṣkarmya-siddhiḥ | niṣkarmatvasya vā niṣkriyātma-rūpāvasthāna-lakṣaṇasya siddhiḥ niṣpattiḥ | tāṃ naiṣkarmya-siddhiṃ paramāṃ prakṛṣṭāṃ karmaja-siddhi-vilakṣaṇāṃ sadyo-mukty-avasthāna-rūpāṃ saṃnyāsena samyag-darśanena tat-pūrvakeṇa vā sarva-karma-saṃnyāsena | adhigacchati prāpnoti | tathā coktaṃ—sarva-karmāṇi manasā saṃnyasya naiva kurvan na kārayann āste iti

Rāmānuja

sarvatra phalādiṣu asaktabuddhiḥ, jitātmā jitamanāḥ, paramapuruṣakartṛtvānusaṃdhānenātmakartṛtve vigataspṛhaḥ, evaṃ tyāgād ananyatvena nirṇītena saṃnyāsena yuktaḥ karma kurvan paramāṃ naiṣkarmyasiddhim adhigacchati paramāṃ dhyānaniṣṭhāṃ jñānayogasyāpi phalabhūtam adhigacchatītyarthaḥ / vakṣyamāṇadhyānayogāvāptiṃ sarvendriyakarmoparatirūpām adhigacchati

Śrīdhara

nanu karmaṇi kriyamāṇe kathaṃ doṣāṃśa-prahāṇena guṇāṃśa eva sampadyata ity apekṣāyām āha asakta-buddhir iti | asaktā saṅga-śūnyā buddhir yasya | jitātmā nirahaṅkāraḥ | vigata-spṛhaḥ vigatā spṛhā phala-viṣayecchā yasmāt saḥ | evambhūtena saṅgaṃ tyaktvā phalaṃ caiva sa tyāgaḥ sāttviko mataḥ (Gītā 18.9) | ity evaṃ pūrvoktena karmāsakti-tat-phalayos tyāga-lakṣaṇena sannyāsena naiṣkarmyasiddhiṃ sarva-karma-nivṛtti-lakṣaṇāṃ sattva-śuddhim adhigacchati | yadyapi saṅga-phalayos tyāgena karmānuṣṭhānam api naiṣkarmyam eva kartṛtvābhiniveśābhāvāt ( yad uktam – naiva kiñcit karomīti yukto manyeta tattvavit (Gītā 5.8) ity ādi śloka-catuṣṭayena ), tathāpy anenokta-lakṣaṇena sannyāsena paramāṃ naiṣkarmya-siddhiṃ sarva-karmāṇi manasā sannyasyāste sukhaṃ vaśī (Gītā 5.13) ity evaṃ-lakṣaṇa-pāramahaṃsyāpara-paryāyām āpnoti

Viśvanātha

evaṃ sati karmaṇi doṣāṃsān kartṛtvābhiniveśa-phalābhisandhi-lakṣaṇān tyaktavataḥ prathama-sannyāsinas tasya kālena sādhana-paripākato yogārūḍhatva-daśāyāṃ karmaṇāṃ svarūpeṇāpi tyāga-rūpaṃ dvitīya-sannyāsam āha asakta-buddhiḥ sarvatrāpi prākṛta-vastuṣu na saktā āsakti-śūnyā buddhir yasya saḥ | ato jitātmā vaśīkṛta-citto vigatā brahma-loka-paryanteṣv api sukheṣu spṛhā yasya saḥ | tataś ca sannyāsena karmaṇāṃ svarūpeṇāpi tyāgena naiṣkarmyasya paramāṃ śreṣṭhāṃ siddhim adhigacchati prāpnoti | yogārūḍha-daśāyāṃ tasya naiṣkarmyam atiśayena siddhir bhavatīty arthaḥ

Baladeva

evam ārurukṣuḥ san-niṣṭho jñāna-garbhayā karma-niṣṭhayānubhūta-svarūpas tataḥ karma-niṣṭhāṃ svarūpatas tyajed ity āha asakteti | sarvatrātmātirikteṣu vastuṣv asakta-buddhir yato jitātmā svātmānandāsvādena vaśīkṛta-manā ataeva vigata-spṛha ātmātirikta-vastu-sādhyeṣu nānā-vidheṣv ānandeṣu spṛhā-śūnyaḥ | svātmānandāsvāda-vikṣepakānāṃ karmaṇāṃ sannyāsena svarūpatas tyāgena paramāṃ naiṣkarmya-lakṣaṇāṃ siddhim adhigacchati yogārūḍhaḥ san | evam evoktaṃ tṛtīye yas tv ātma-ratir eva syād (Gītā 3.17) ity ādinā