Secret.

གསང་བ་
Tibetan: Sangwa
English: Secret, hidden

Many of the Buddhas' teachings, especially those of the Vajrayana, are described as being secret.  Their are many lineages of esoteric teachings that descend from Tibet, many which are dying out as the tradition meets with a global culture and modern civilization. 

Many might ask, if the teachings are dying out, what is the point in keeping them secret?

We think of secrecy or hidden teachings in which the practitioners are sworn to silence, vowing not to disclose the practice.  That is our ordinary perception and understanding of these teachings, just talk about them and they will stay alive and spread, right?

But the teachings are actually secret because they they are beyond mere words.  They can be shown, witnessed or revealed, but they cannot be explained.

The teachings remain secret unless we commit ourselves to them, unless we become the working basis for the practice to unfold.  The act of working through the practice reveals that which is beyond description.

The life of the teachings then does not depend on simply sharing the teachings, it depends on people committing their lives to their practice.  Once we have received the blessings of the lineage, it is up to us to engage in the practice and develop it to its maturation.  

The practice tradition is the holder of the secret teachings and it is this tradition that we must strive to keep alive.