Definition of proof:
(n) :
any effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial; that degree of evidence which convinces the mind of any truth or fact, and produces belief; a test by facts or arguments that induce, or tend to induce, certainty of the judgment; conclusive evidence; demonstration
"for whatsoever mother wit or art Could work, he put in proof. -
w:Spenser."
(adj) :
used in proving or testing; as, a proof load, or proofcharge; firm or successful in resisting; as, proof against harm;
waterproof; bombproof