eavesdropper vs tapper

eavesdropper and tapper both are nouns.

Word	Noun	Adjective	Verb	Adverb
eavesdropper	Yes	No	No	No
tapper	Yes	No	No	No

As nouns, tapper is a hyponym of eavesdropper; that is, tapper is a word with a more specific, narrower meaning than eavesdropper:

Other hyponyms of eavesdropper include phone tapper, wiretapper.

eavesdropper (noun)	tapper (noun)
a secret listener to private conversations	someone who wiretaps a telephone or telegraph wire
	a tavern keeper who taps kegs or casks
	a worker who uses a tap to cut screw threads
	a dancer who sounds out rhythms by using metal taps on the toes and heels of the shoes
	a person who strikes a surface lightly and usually repeatedly