In English language books about Buddhism and spiritual work, you often find the word detachment. Unfortunately, many people interpret this to mean being stoic or indifferent. By looking at the definitions of the original Pali and Mandarin terms, I show that this is not the case.
The Pali word that is often translated as detachment is nekkhamma. Nekkhamma can also mean renunciation or freedom from sensual desire. In my own practice, this last definition makes the most sense. I see it as letting go of any form of greed or grasping.
Tanha is a Pali word that literally means thirst. It is often translated craving.
The Buddhist tradition identifies taṇhā as a self-centered type of desire that is based in ignorance. This type of desire is contrasted to wholesome types of desire such as the desire to benefit others or to follow the Buddhist path. 
From the above, you can see there is healthy desire and unhealthy desire. Since there are healthy desires, it is clear that desirelessness is not the goal.
Another interpretation of detachment that resonates with my experience is that it means detachment from clinging selfishly to an agenda.
In Zen, the word that is often translated as detachment is wú niàn. Wú niàn is a Mandarin term that means unstained by thought. This means to experience yourself as having thoughts, rather than being your thoughts. Who you are is the spaciousness in which those thoughts arise. This gives you choice. You can love more freely if you are not mistaking your thoughts for yourself.
One thing that Buddhists cultivate is equanimity. The near enemy of equanimity is indifference.
The near enemy is often mistaken for the real deal. In this case, Buddhist practitioners can mistake indifference for equanimity. This is where a teacher is useful. She or he will recognize this and point it out.
Also, desire motivates you to take action. Right Action is part of the Noble Eightfold Path.
For more about being unstained by thought, see my blog: HOW TO RELATE TO YOUR THOUGHTS DURING MEDITATION
©2016 Stephen L. Martin