i Register
In some senses, knocker is marked as derogatory, informal, slang. Watch for register when choosing this word.
noun
A device, usually hinged with a striking plate, used for knocking on a door.
Knockers in this part of the world seem intended for ornament only, — nobody seems to pay any attention to them when they’re used.
His tongue became a staircase, his uvula the knocker / Of an ornate wooden door that led me straight into my future
A person who knocks.
He was a loud knocker. Despite my usual timidity, after a bit I opened the door.
A critic; one who disparages.
"I try to give everybody credit," declared the old man. "I am not a knocker. I am not too good for this world."
A person who knocks (denigrates) something.
A person's breast, especially if large.
name
A surname.