What is 'letting go' and 'detachment' actually? My experience of letting go and detaching

I know that meditating on letting go and detachment is a fruitful activity. I experience physical discharge when I see I am holding on to something, that isn't true, and I let it go. In other words, I detach from it.

As a variant to this meditation practice I also attach again. That is, I try to get myself back into that feeling that I had when I was attached. The moment that I notice the slightest mental activity of getting carried away again, I reevaluate that it isn't true and keep my focus there until I feel I am detaching again. I do this a couple of times until I know longer feel any interest arise anymore when I focus on attaching, and thus, the attachment doesn't happen anymore. To me it is like getting bored with the subject. There is nothing in it for me anymore that I want to grasp. It seems that all energy that caused any attachment dissipated. 

Stop creating mental constructs instead of letting go of them

Now on the the purpose of this question. Today I realized that what I attach to is always a mental construct. And that mental construct is always created by myself. Then I came to think about the words 'letting go' and 'detaching'. These words seem to imply there is something there, that exist on their own, of which you 'need' to 'let go' and 'detach'. There is something, but not there in objective reality, but here in subjective mental constructs. What if, the moment I observe a mental construct, I realize I don't want to create that mental construct in the first place. Then there is nothing to let go, there is nothing to detach from, as it simply doesn't exist anymore. It isn't being created in the first place. That puts me in the chair of being the 'creator' of all my experience. So then I do not practice the 'letting go' and 'detachment' from anything anymore, I practice the 'stop creating' of unfruitful mental constructs, which leaves energy for creating mental activity that is fruitful.

Questions:


Then I came to wonder, did Buddha really ment 'letting go' and 'detach'?
What are the actual sanskrit and pali terms for 'letting go' and 'detach'? 
And do they really mean the same, or is it more like 'Dukkha' which is best translated to 'suffering', while it is not exactly the same. But suffering is the closest matching description.
What are the actual sanskrit and pali terms for 'letting go' and 'detach'?

Quoting from "Re: What is the last thing to let go?":


  In the Suttas paṭinissagga and its synonym vossagga are the words that usually get translated ‘relinquishment’, ‘letting go’ and suchlike. What is relinquished is appropriation (ādāna) which is a term for taṇhā and upādāna.


And:


  Paṭinissagga (letting go) is the broad term and then nekkhamma (letting go) is a more specialised one. Nekkhamma is paṭinissagga with respect to desire for sense-pleasures.