Synonyms of diabolical in English:

diabolical


See US English definition of diabolical

See UK English definition of diabolical

See Spanish definition of diabólico

adjective

1‘his diabolical skill’

SYNONYMS
devilish, diabolic, fiendish, satanic, Mephistophelian, demonic, demoniacal, hellish, infernal, evil, wicked, ungodly, unholy
rare cacodemonic

2‘the team manager was sacked after that diabolical performance’

SYNONYMS
very bad, poor, dreadful, awful, terrible, frightful, disgraceful, shameful, lamentable, deplorable, appalling, atrocious
inferior, substandard, mediocre, unsatisfactory, inadequate, second-rate, third-rate, shoddy, inept, bungling, hopeless
informal crummy, dire, dismal, godawful, shocking, abysmal, bum, rotten, pathetic, woeful, pitiful, lousy, useless, the pits
British informal duff, rubbish, ropy, chronic, a load of pants, poxy
vulgar slang crap, crappy, shitty
North American vulgar slang chickenshit, hellacious
archaic direful
rare egregious
ANTONYMS

excellent

3‘a diabolical liberty’

SYNONYMS
very great, extreme, excessive, undue, inordinate, immoderate, unconscionable, outrageous
uncalled for, unprovoked, intolerable, unacceptable, unreasonable, unjustifiable, unwarrantable, without justification, indefensible, inexcusable, unforgivable, unpardonable