self-serving

Definition from Nolo’s Plain-English Law Dictionary

Refers to a statement or answer to a question that serves no purpose and provides no evidence, but only argues or reinforces the legal position of a particular party in a lawsuit. An example would be a lawyer asking his own client: "Are you the sort of person who would never do anything dishonest?" A judge may disallow this kind of question unless there is some evidentiary value.

Definition provided by Nolo’s Plain-English Law Dictionary.