fiendish fiendish /ˈfiːndɪʃ/

adjective

1. () Extremely evil or cruel; expressive of cruelty or befitting hell  ( demonic , diabolic , diabolical , fiendish , hellish , infernal , satanic , unholy )
   extremely evil or cruel; expressive of cruelty or befitting hell
    Something demonic in him--something that could be cruel
   something demonic in him--something that could be cruel
    Fires lit up a diabolic scene
   fires lit up a diabolic scene
    Diabolical sorcerers under the influence of devils
   diabolical sorcerers under the influence of devils
    A fiendish despot
   a fiendish despot
    Hellish torture
   hellish torture
    Infernal instruments of war
   infernal instruments of war
    Satanic cruelty
   satanic cruelty
    Unholy grimaces
   unholy grimaces