Substantiate (verb)

1. To provide evidence or proof to support a statement or claim.
2. To establish the truth or validity of something through the provision of evidence or proof.

Origin:

Derived from the latin word "substantia" meaning "substance" and the suffix "-ate" meaning "to make".

Examples:

1. He was asked to substantiate his claims with evidence.
2. The witness was asked to substantiate her testimony.
3. The company was unable to substantiate the claims made in their advertising.
4. The scientist was able to substantiate his theories with experimental data.
5. The lawyer tried to substantiate his client's alibi with witnesses.