Listen in (9)
'listen in' is the definition.
(synonyms)
This is all the clue.
(Other definitions for eavesdrop that I've seen before include "Listen secretly to private talk" , "Listen at windows" , "spy" , "Deprave so to listen secretly" , "Listen carefully" .)
(Other definitions for interfere that I've seen before include "Poke one's nose in" , "Obstruct, pry" , "Meddle, butt in" , "Come between, intervene" , "Intruder does" .)
'listen in' is the definition.
(earwig can mean to secretly listen to something)
This is the entire clue.
(Other definitions for earwig that I've seen before include "Go in for eavesdropping" , "An insect, I wager (anag.)" , "Creepy type" , "Eavesdrop (informal)" , "Insect with pincer-like tail" .)