Vairagya
वैराग्य (vairāgya)
Non-attachment - not coldness, but the loosening of the grip by which outcomes hold the mind hostage.
Vairagya is routinely mistranslated as indifference, which ruins it. The word describes fading colour - raga is passion, literally a dye - and names the process by which things stop staining the mind. One still acts, loves, builds; one is simply no longer owned by the results.
The Gita pairs it permanently with abhyasa, practice: effort without non-attachment curdles into anxiety, and non-attachment without effort decays into indifference after all. The two correct each other.
A fair test of vairagya is not how little you want, but how you behave when you do not get it. The practice is small and constant: doing the work well, then loosening the fingers - once per task, once per day, for years.