killer

noun

1. (countable, uncountable)One who or that which kills.

   “There’s a killer on the loose.”

   “My cat is a habitual bird killer.”

   “Carbon monoxide is a silent killer.”

2. (countable, figuratively, uncountable)That which causes stress or is extremely difficult, especially that which may cause failure at a task.

   “That test was a killer.”

   “The final hill in the race course was a killer.”

3. (countable, figuratively, uncountable)Something that is so far ahead of its competition that it effectively kills off that competition.

   “Digital streaming platforms are CD killers.”

4. (countable, figuratively, uncountable)A remarkably impressive person or thing.

   “Picture perfect, you don't need no filter / Gorgeous, make 'em drop dead, you're a killer”

5. (uncountable)A knockout form of darts or pool involving several players.
6. (abbreviation, alt-of, countable, ellipsis, uncountable)Ellipsis of killer whale.

   “There is, however, one species of whale that habitually preys upon other warm-blooded animals—the killer whale. Really a large dolphin, the killer was classified by Linnaeus as Orcinus orca, and by Cope as Grampus rectipinna.”

7. (countable, uncountable)A club used for killing fish.
8. (countable, uncountable)A particularly heavy type of handstamp, or portion of one, often obscuring a large part of the postage stamp.
9. (countable, uncountable)Synonym of virama (“kind of diacritical mark”).

   “For example, although the ‘vowel killer’ diacritic may be called a ‘pulli’ in Tamil, it is still referred to by the Unicode character names as a ‘virama’.”

   “Thai words that have been borrowed from Sanskrit, Pali and English usually try to retain as much of the original spelling as possible; as this will often produce pronunciations that are impossible or misleading, a ‘killer’ symbol is placed above the redundant consonant to indicate that it may be ignored”

   “Sometimes the ‘killer’ sign, called kaaran in Thai, cancels out not only the consonant above which it appears, but also the one immediately preceding it.”

adj

1. (slang)Excellent, very good, cool.

   “killer feature”

   “killer view”

   “It all says that Elephant's Memory is a killer band.”

   “This is followed by a recipe for that very killer dish: "Eat and remember this, the greediest of all Popes" is their merry exhortation.”

   ““Ahhh, Avery,” shouted the Yurtmeister after a full hour of intense volleyball. “That last serve was absolutely killer.””

2. Causing death, destruction, or obliteration.

   “killer bee”

   “killer robot”

3. Distressing, uncomfortable.

   “I had a killer headache this morning.”