Caveat /(?)/

Ca·ve·at

Caveat

n.
  1. A notice given by an interested party to some officer not to do a certain act until the party is heard in opposition; as, a caveat entered in a probate court to stop the proving of a will or the taking out of letters of administration, etc. (Law)
  2. A description of some invention, designed to be patented, lodged in the patent office before the patent right is applied for, and operating as a bar to the issue of letters patent to any other person, respecting the same invention. (U. S. Patent Laws)
  3. Intimation of caution; warning; protest.
    We think it right to enter our caveat against a conclusion.
    — Jeffrey.

Phrases & Compounds
Caveat emptor
let the purchaser beware, i. e., let him examine the article he is buying, and act on his own judgment.