/kil"euhr/ , n.
1. a person or thing that kills.
2. See killer whale .
3. a device used by a post office for printing cancellations on postage stamps.
4. a mark of cancellation made on a postage stamp.
5. Slang. something or someone having a formidable impact, devastating effect, etc.: The math test was a real killer.
adj. Slang.
6. severe; powerful: a killer cold.
7. very difficult or demanding: a killer chess tournament.
8. highly effective; superior: a killer recipe for fried chicken.
[ 1525-35; KILL 1 + -ER 1 ]