rapper vs doorknocker

rapper and doorknocker both are nouns.

Word	Noun	Adjective	Verb	Adverb
rapper	Yes	No	No	No
doorknocker	Yes	No	No	No

As nouns, rapper and doorknocker are synonyms defined as:

rapper and doorknocker: a device (usually metal and ornamental) attached by a hinge to a door

Other synonyms of rapper include knocker.

rapper (noun)	doorknocker (noun)
a device (usually metal and ornamental) attached by a hinge to a door	a device (usually metal and ornamental) attached by a hinge to a door
someone who performs rap music