to stand in witness: to act as a witness. Scottish. Obsolete.

To testify, bear witness; to testify to, attest; esp. to give evidence upon oath in a court of law… gen. To testify, bear witness, affirm, assert.

intransitive. To declare upon oath; to testify, bear testimony. Also figurative.

With reference to legal evidence. intransitive. To give evidence, testify, appear as a witness. Obsolete.