There has to be definitive proof of drug use, such as a witness who is willing to come forward by name.

But now we have definitive proof that they didn't mean it.

It's the definitive proof that I have something unique and gives the company added value.

But biological evidence is far less likely to be available or provide definitive proof in other kinds of cases.

Despite this, definitive proof of the relation has yet to be provided.

There's not definitive proof as to the age of the universe.

Notwithstanding, there does not seem to be any definitive proof of what the play was originally called or why.

For definitive proof, there was a need to develop a gene test.

Opponents say that is too simple and want definitive proof.

In the social sciences definitive proof develops over many years.