The word "veil" itself can function as a noun, meaning a piece of fabric worn to cover the face or head, or as a verb, meaning to cover or hide something.
It is possible you are thinking of a different word, or perhaps you're looking for a prefix that means something similar to "veil" such as:
* Ob-: meaning "against" or "in the way of", as in obstacle.
* Dis-: meaning "not" or "opposite of", as in disguise.
* Cover-: meaning "to hide or protect", as in cover-up.
Please clarify your request if you are looking for a specific term related to "veil".