From Longman Dictionary of Contemporary Englishmaniacma‧ni‧ac /ˈmeɪniæk/ ●○○ noun [countable] 1 informalCRAZY someone who behaves in a stupid or dangerous way SYN lunatic He drove like a maniac to the hospital. Suddenly this maniac ran out into the middle of the road.2 → religious/sex maniac3 someone who is mentally illhomicidal maniac (=someone who kills people)
Examples from the Corpus
maniac• He drives like a maniac.• The occupant of the stolen car was driving like a maniac.• I was running around the dance floor like a maniac.• I signed it without speaking, incredibly delighted, grinning like a maniac.• I had to calm down, and not lurch around in traffic like a maniac.• He was one of those smiling gloomy maniacs.• He didn't smile, or laugh like maniacs are supposed to.• Scientists on the other side were maniacs, to a man.like a maniac• Jim had his foot on the floor, swinging around potholes, driving like a maniac.• She packed her bag together and drove like a maniac to the mikva.• I was running around the dance floor like a maniac.• I signed it without speaking, incredibly delighted, grinning like a maniac.• Just as the train pulled out of the station a lorry load of soldiers drove in like maniacs.• He didn't smile, or laugh like maniacs are supposed to.• I looked like a maniac, of course, with my hair all wet, my shoes sopping.• I had to calm down, and not lurch around in traffic like a maniac.homicidal maniac• Even if he is murdered by a homicidal maniac he has chosen to be at a certain place at a certain time.• Kerns is Sara Rayner, whose orderly little life comes apart when she is attacked and raped by a homicidal maniac.• But none as far as I know is a homicidal maniac.• Could be a concerned taxpayer, a homicidal maniac, some trial lawyer.• a homicidal maniacOrigin maniac (1500-1600) Late Latin maniacus, from Greek maniakos, from mania; → MANIA 