Synonyms for "ordering to testify" are many and varied, depending on the context and the legal system involved. Some possible alternatives to this phrase might include "subpoenaing to testify," "compelling to testify," or "mandating testimony" in a court of law. Another possible synonym might be "summoning to testify" in certain jurisdictions, or "requiring testimony" in administrative or regulatory proceedings. Regardless of the terminology used, the basic idea behind "ordering to testify" remains the same: requiring someone to appear under oath and answer questions related to a legal matter, either as a witness or a party to the case.