In plain words
dwelling in solitude, eating lightly, controlling speech, body, and manas, constantly devoted to dhyāna and yoga and taking refuge in Vairāgya,
Word for word
resorting to solitude, eating lightly, with speech, body and mind controlled, constantly devoted to dhyāna and yoga, having fully taken refuge in dispassion,
The commentators
Bhagavadgītābhāṣyam
ततः —
विविक्तसेवी अरण्यनदीपुलिनगिरिगुहादीन् विविक्तान् देशान् सेवितुं शीलम् अस्य इति विविक्तसेवी, लघ्वाशी लघ्वशनशीलः — विविक्तसेवालघ्वशनयोः निद्रादिदोषनिवर्तकत्वेन चित्तप्रसादहेतुत्वात् ग्रहणम् ; यतवाक्कायमानसः वाक् च कायश्च मानसं च यतानि संयतानि यस्य ज्ञाननिष्ठस्य सः ज्ञाननिष्ठः यतिः यतवाक्कायमानसः स्यात् । एवम् उपरतसर्वकरणः सन् ध्यानयोगपरः ध्यानम् आत्मस्वरूपचिन्तनम् , योगः आत्मविषये एकाग्रीकरणम् तौ परत्वेन कर्तव्यौ यस्य सः ध्यानयोगपरः नित्यं नित्यग्रहणं मन्त्रजपाद्यन्यकर्तव्याभावप्रदर्शनार्थम् , वैराग्यं विरागस्य भावः दृष्टादृष्टेषु विषयेषु वैतृष्ण्यं समुपाश्रितः सम्यक् उपाश्रितः नित्यमेव इत्यर्थः ॥ ५२ ॥
In plain words
That being so —
'Viviktasevī' means: it is simply his habit to seek out secluded places — forests, riverbanks, sandbanks, mountains, caves. 'Laghvāśī' means someone in the habit of eating lightly — and both solitude and light eating get mentioned here because they clear the mind, by keeping faults like excess sleep at bay. 'Yatavākkāyamānasaḥ' means: for this person steadfast in knowledge, this ascetic, speech, body, and mind are all under firm control. Once all his organs have quieted down like this, he is 'dhyānayogaparaḥ' — dhyāna means contemplating the Self's own true nature; yoga means bringing the mind to one-pointed focus on the Self; and he is someone for whom these two are his highest priority. As for 'always' — that word is there precisely to rule out the idea that he should alternate this with other duties, like reciting mantras. 'Vairāgya' simply means the state of dispassion — freedom from craving toward anything, whether seen here or promised hereafter. 'Samupāśritaḥ' means having truly, rightly taken refuge in that dispassion, and doing so constantly, without a break — that is the meaning.
Close to the Sanskrit
Thence —
'Viviktasevī' means: 'to resort to secluded places, such as forests, rivers, sandbanks, mountains, and caves, is his habit' — thus one is called 'viviktasevī'. 'Laghvāśī' means one whose habit is light eating — the mention of resorting to solitude and light eating is because of their being causes of mental clarity, by removing faults such as excess sleep. 'Yatavākkāyamānasaḥ' means: speech and body and mind are controlled, restrained, for whom — that one steadfast in knowledge, the ascetic steadfast in knowledge, would be one whose speech, body, and mind are controlled. Thus, being one whose every organ is stilled, he is 'dhyānayogaparaḥ' — dhyāna means contemplation of the Self's own true nature; yoga means one-pointed concentration upon the Self; those two, as supreme, are to be practiced by whom — he is 'dhyānayogaparaḥ'. 'Nityam' — the mention of 'constantly' is for the purpose of showing the absence of any other duty such as mantra-recitation and the like. 'Vairāgya' means the state of dispassion, that is freedom from craving regarding objects seen and unseen; 'samupāśritaḥ' means rightly resorted to, that is relied upon, constantly — this is the meaning.