ADJ
big, major
Heart disease remains a major killer in developed countries today.
real
The police finally arrested the real killer after months of investigation.
alleged | convicted | notorious | brutal, vicious | crazed, psychopathic | mass, serial | contract, hired
child, wife, etc.
The serial killer was finally captured after evading police for nearly two decades.
giant
The local team became giant killers when they defeated the championship favorites in an upset victory.
VERB + KILLER
hunt, track down | catch, find
KILLER + VERB
strike
A serial killer struck three times in the city last year before police caught him.
KILLER + NOUN
bug, disease, virus
Malaria remains a killer disease in many tropical countries around the world.
instinct
She has the killer instinct needed to succeed in competitive business negotiations.
blow
The boxer landed a killer blow in the final round and won the match.