proof
UK: pruːf | US: pruːf
n. evidence establishing a fact or truth
n. a test or trial to demonstrate quality or validity
vt. to make resistant or impervious (e.g., proofread, waterproof)
The word "proof" traces back to Latin probare ("to test, approve"), combining pro- ("forward") and -bare (a variant of -bhrū-, meaning "to see/judge"). It entered Old English via Old French preuve, evolving from the idea of "testing forward" (evaluating validity) to its modern meanings of evidence or resistance. The verb form (e.g., "proofread") retains the original sense of testing for errors.
The scientist presented proof of her theory.
This fabric is proof against water.
He proofed the document carefully.
The lawyer demanded concrete proof.
The recipe requires proofing the dough.