B.G 2.50

बुद्धियुक्तो जहातीह उभे सुकृतदुष्कृते। तस्माद्योगाय युज्यस्व योगः कर्मसु कौशलम् ॥२-५०॥

buddhiyuktō jahātīha ubhē sukr̥taduṣkr̥tē। tasmādyōgāya yujyasva yōgaḥ karmasu kauśalam ॥2-50॥

[ बुद्धि-युक्तो जहाति इह उभे सुकृत-दुष्कृते। तस्मात् योगाय युज्यस्व योगः कर्मसु कौशलम् ॥२-५०॥
buddhi-yuktō = possessed with the knowledge (of the lord); jahāti = renounce; iha = here; ubhē = both; sukr̥ta-duṣkr̥tē = results of good and bad deeds; tasmāt = therefore; yōgāya = in Yōga; yujyasva = engagge in; yōgaḥ = Yōga is; karmasu kauśalam = skill in the performance of the actions (for His sake);]

Possessed with the knowledge of the lord he renounces here and now the results of both the good and bad deeds. Therefore, engage yourself in Yōga. Yōga is skill in performing the actions for His sake.

Gīta Tātparya 2.50

'karmakauśala' - performing action for the lord's sake. 'budidhaḥ' - one who possesses the knowledge of the lord.

यथावत् विष्णुं ज्ञात्वा तदर्थत्वेन कर्मकरण मित्येतत् कर्मकौशलमेव योगः। भगवज्झानमेव बुदि्धः ॥५०, ५१॥

yathāvat viṣṇuṁ jñātvā tadarthatvēna karmakaraṇa mityētat karmakauśalamēva yōgaḥ। bhagavajjhānamēva budidhaḥ ॥50, 51॥

[yathāvat = properly; viṣṇuṁ = lord Vishnu; jñātvā = knowing; tadarthatvēna = for His purpose; karmakaraṇa = performing action; mityētat = this is; karmakauśalamēva = 'karmakauśala' is only; yōgaḥ = Yōga; bhagavajjhānamēva = one who possesses the knowledge of the lord; budidhaḥ = is called 'budidhaḥ']

The Yōga is 'karmakauśala' which is nothing but knowing lord Vishnu properly and performing action for His sake. The word 'budidhaḥ' means one who possesses the knowledge of the lord.