What is the legal definition of grave abuse of discretion?
“Grave abuse of discretion,” under Rule 65, has a specific meaning. It is the arbitrary or despotic exercise of power due to passion, prejudice or personal hostility; or the whimsical, arbitrary, or capricious exercise of power that amounts to an evasion or refusal to perform a positive duty enjoined by law or to act at all in contemplation of law. For an act to be struck down as having been done with grave abuse of discretion, the abuse of discretion must be patent and gross.”1
By grave abuse of discretion is meant, such capricious and whimsical exercise of judgment as is equivalent to lack of jurisdiction. The abuse of discretion must be grave as where the power is exercised in an arbitrary or despotic manner by reason of passion or personal hostility and must be so patent and gross as to amount to an evasion of positive duty or to a virtual refusal to perform the duty enjoined or to act at all in contemplation of law.2
1FAJARDO vs. CA, G.R. No. 157707, 2008 October 29.
2 PRODUCERS BANK OF THE PHILIPPINES vs. NLRC, et. al., G.R. No. 76001, 1988 September 5.