expression, noun, na-adjective
real nuisance; great inconvenience
Ironic expression meaning that something is a great nuisance or trouble, especially when one is inconvenienced by someone else's problems through no fault of one's own. The いい is sarcastic, implying 'what a fine mess'.
隣の騒音は本当にいい迷惑だ。
The noise from next door is a real nuisance.
彼の借金のせいで、こっちまでいい迷惑を被った。
Because of his debts, I ended up being greatly inconvenienced too.
迷惑 is a straightforward noun/adjective meaning 'nuisance' or 'trouble'. いい迷惑 adds an ironic twist, emphasizing the speaker's frustration.
Compound of いい (good) and 迷惑 (nuisance). The いい is used ironically to express that something is a 'fine' nuisance, i.e., a real trouble.