From Longman Dictionary of Contemporary Englishkillerkill‧er1 /ˈkɪlə $ -ər/ ●●○ noun [countable] 1 KILLa person, animal, or thing that kills Heart disease is America’s number one killer. the hunt for her killers weed killer → serial killer at serial2(1)2 informalGOOD/EXCELLENT something or someone that is very difficult, tiring, or boring The new project is a killer.3 informal something that is very exciting or impressive I’m not saying the film is a killer, but it’s cool.
Examples from the Corpus
killer• The judge described him as "a cold-blooded killer".• He'd been beaten about the head. 60 police officers are now searching for his killer.• But our instinctive need to fill the vacuum inspires us to the ultimate irony: We turn 12 average citizens into killers.• Tracy's schedule is a real killer.• And the real killer is, in two weeks, they will probably give the Broncos a healthy workout.• Brilliant detective work with a little luck tossed in to catch the savvy killer.• Dr Shipman is the biggest serial killer of all time.• Even serial killers get cost-of-living raises if they happen to have a pension adjusted for inflation.• The victim's best friend, Joanne, is convinced the killer is local.• Police are searching for the killer of a 9 year old boy.• Police are still searching for the killer.• Meanwhile, a reward has been offered for information which might lead to the arrest of the killer of Arthur Brumhill.• From Pennsylvania came details of a group murder, followed by the suicide of two of the killers.killerkiller2 adjective [only before noun] 1 very harmful or dangerous a killer hurricane a swarm of killer bees2 informal very attractive, good, impressive etc a book called ‘How to Build a Killer Website’killer heels (=women’s shoes with very high heels)3 → killer instinctExamples from the Corpus
killer• The concert was killer.• A swarm of killer bees has attacked 70 children in a village in northern Mexico.• a killer cyclone• Killer floods and hurricanes in Asia have destroyed whole towns.• If you guys like garlic, this pickled garlic is killer stuff. 