What is Karma in the Bhagavad Gita?
Karma simply means action. The popular sense of karma as cosmic payback is a later and much narrower use of a word that, in the Gita, mostly means what you are doing right now.
The book's claim is that action leaves a residue. Not a record kept by someone else, but a grain laid down in you: what you do repeatedly becomes what you are disposed to do. That is why 18.17 says a person free of the sense of being the doer is not bound by what he does. The binding was never in the deed. It was in the claim on it.
This is also why the Gita refuses the obvious escape. You cannot stop acting. 18.11 says plainly that nobody wearing a body can give up action entirely, because having a body is itself continuous activity. So the solution cannot be to act less. It has to be a change in how action is held, which is what karma yoga means: the same work, done without the grip on what it will return.
The verses 21
2.47
Your claim is on the action alone, never on its fruits.
2.48
Stand in yoga and do your work, Arjuna, letting go of the holding-on.
2.49
Work done for what it will fetch is far below work done from a settled mind.
3.4
You do not get free of action by not starting anything.
3.5
Nobody stays still even for a moment.
3.8
Do the work that is yours to do.
3.9
Work binds a person, except when it is done as an offering.
3.14
Living things come from food.
3.15
Know that action comes from what was spoken, and what was spoken comes from what does not perish.
4.16
Even the wise are confused about what counts as acting and what counts as not acting.
4.17
You have to understand action, and you have to understand wrong action, and you have to understand not acting.
4.18
Whoever sees not-acting in action, and acting in not-acting, is the one with understanding among people.
5.10
Whoever acts placing his actions in the infinite, having given up attachment, is not stained by wrong - as a lotus leaf is not wetted by water.
8.3
Krishna said: The imperishable, the highest, is Brahman.
18.12
Unwanted, wanted and mixed: the fruit of action comes in those three kinds, after death, for those who did not let go.
18.13
Learn from me the five causes, mighty-armed one, that the reckoning of things says must come together for any action to be completed.
18.14
The place it happens, the one doing it, the different instruments, the various separate efforts, and the fifth of them: what is simply given.
18.15
Whatever a person sets in motion with body, speech or mind, whether it is right or whether it is the opposite, these five are what bring it about.
18.23
Work that is in order, done without clinging, without liking or disliking, by someone not reaching for the fruit: that work is called clear.
18.24
But work done by someone chasing what he wants, or done with the sense of I, and done with a great deal of strain: that is called driven.
18.25
Work begun out of confusion, with no thought for what follows, for what it costs, for the harm it does, or for whether you can actually do it: that is called dark.