Englishmaniac
noun
1 a homicidal maniac:
lunatic, madman, madwoman, mad person, deranged person, psychopath, psychotic;
informal loony, fruitcake, nut, nutcase, nutjob, cuckoo, psycho, screwball, head case, headbanger, sicko;
British, informal nutter;
Scottish, informal radge;
North American, informal crazy, kook, meshuggener, nutso;
US, informal wing nut.
maniac Oxford Dictionary of English