Naishkarmya is one of the important concepts of the Bhagavad Gita. Naishkarmya in Gita means giving up of doing Karma.
Karma in Sanskrit means a deed, an act, action or whatever one performs or does in practice. The Karma doctrine involves a foundational belief of Hindu philosophy, namely, that every deed leaves its effect (Karma-phala or Karmasaya) which the doer is bound to enjoy in the present life or in a future life.
Karmasya Karma is looked upon as the binding force which one must overcome in order to attain mukti (freedom). It is wrong conception that by giving up doing karma (which is called Naishkarmya) one can attain freedom.
Sannyasa (the way of renunciation) has come to enjoy a great prestige among religious-minded people. But merely by giving up karma one cannot become a renunciate.
In the Bhagvad Gita (III .4), this fact is emphasized by saying that Naishkarmya does not mean only giving up all deeds, mukti cannot be attained merely by renouncing the world.
Giving up actions outwardly while entertaining cravings in one’s mind is called hypocrisy (mithyachara) in the Bhagavad Gita (III. 6).
The most important fact about naishkarmya is the control of the senses by the mind, and undergoing all actions in life with a detached mind (asaktah). Such a person is called a karmayogin, and he is said to succeed in achieving mukti (Gita III.7)
Giving up all actions and deeds is impossible in life, but giving up craving for the fruits (karma phala) brings the highest goal of naishkarmya siddhi into reality (Gita XVIII 11, 49).
Bibliography
The Yoga of the Bhagavad Gita (1948) Sri Krishnaprem – John M Watkins London
Encyclopedia of Hinduism Volume VII page 329 - IHRF