Compellability of witness answers: court decides if witness must answer, weighing relevance, credibility, proportionality, and adverse inference. Court discretion governs compelling witnesses to answer questions otherwise irrelevant, with power to warn a witness that answering is not obligatory. In exercising that discretion the Court must consider whether the imputation would materially affect the witness's credibility on the subject of testimony, whether the imputation is remote or slight in effect, whether there is a disproportion between the imputation's importance and the evidence's importance, and the Court may draw an adverse inference from refusal to answer.