Noun
(law) The rendering of a decision by a court that is so unreasonable in light of the facts of the case or is such an unreasonable deviation from legal precedent that it must be reversed.
(law) Any action by a government official by which that official renders decisions for a clearly improper purpose.
Source: en.wiktionary.orgd) all informal practices of similar import and effect, which the Court similarly deems to be acts of grave abuse of discretion amounting to lack or excess of jurisdiction; and. Francis Escudero