tapper vs eavesdropper

tapper and eavesdropper both are nouns.

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

As nouns, eavesdropper is a hypernym of tapper; that is, eavesdropper is a word with a broader meaning than tapper:

tapper (noun)	eavesdropper (noun)
someone who wiretaps a telephone or telegraph wire	a secret listener to private conversations
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