1.Definition: especially indicating a form of prosecution in which proceedings are secret and the accused is questioned by a prosecutor who acts also as the judge

2.Definition: having the authority to conduct official investigations

"The inquisitorial power of the Senate"

3.Definition: marked by inquisitive interest; especially suggestive of an ecclesiastical inquisitor

"The press was inquisitorial to the point of antagonism", "A practical police force with true inquisitorial talents"