Supportment: Was what the speaker said backed up by proof?

What could these hounds mean by proof?

Unsupported by further proof or testimony, these links were insufficient to convict the three men that The Shadow had named.

If that be Styllis, by proof of his abilities, good.

And knowing him a thoroughly manly man, why should she be distressed by proof of his masculinity?

Mathematicians resolve the truth or falsity of conjectures by mathematical proof.

He shall taste of my despair, and learn by proof in some wild hour how much the wretched dare.

He cannot connect me by proof with this matter, but he may suspect me.

He was on shore, unemployed, until in some way he came by proof that the man had not in fact been killed by Leander's fire.

We have to reach an agreement on what we mean by proof.