I am made when lips refuse to open, kept alive by the teeth that lock the door. I vanish the moment I’m named, yet if you bury me I only grow. I have no weight, no colour, no sound, and still I can topple kings and drown a town. What am I?

I’m kept by those who lose me, lost by those who keep me. Spoken when silent, silenced when spoken. I’m the answer to no question, yet questioned by every answer. Found in the void, gone in the crowd. I shape thought without form. What am I?

I am an odd number. Take away one letter and I become even. What am I?

Forward I am more than heavy, but backward I am not.

First is the first of first, last is the last of last, the other two are between you!