knock

/nɒk/ noun [C]

Definition

› a situation in which something is badly affected: Sales of champagne were up over the key Christmas period despite earlier fears of a knock in consumer confidence.

› informal a bad experience: take/suffer/have a knock In him, we see a man, toughened by his share of hard knocks, who's had to struggle for every success.

› a criticism of someone or something: a knock on sb/sth The biggest knock on internet phones is that they're only as reliable as your broadband connection.

(Definition of knock noun from the Cambridge Business English Dictionary © Cambridge University Press)