"void dire" comes from the Old French words meaning "true" and "say". http://dictionary.law.com/Default.aspx?selected=2229
In this case, void dire refers to when an attorney challenges a prospective juror due to suspicion of a bias against the attorney's case. Here, Phil meant to show Poole's evidence to the judge, but not the all-white jury, due to their obvious prejudice against Ronald and his case.
Submitted by student authors: Robert Kobet and Laura Moreton