godan verb (-ru)
be in a slump; have no customers; be dead
Slang term used for businesses or events that are extremely quiet with few or no customers. Derived from the idiom 閑古鳥が鳴く (a cuckoo sings), implying emptiness.
See also: 閑古鳥が鳴く (かんこどりがなく)
今日は店がカンコってるな。
The shop is really dead today, huh.
新しく開
It seems the newly opened café is already in a slump.