Select the most appropriate meaning of the given idiom “Knock down”

Select the most appropriate meaning of the given idiom "Knock down"
A: To refused
B: To accept
C: To Proceed
D: To fell something

The idiom “knock down” means to strike something so it falls. It can be used literally for objects or metaphorically in arguments or competition. Idioms enrich language by providing figurative meaning beyond literal interpretation.