Pride And Prejudice· Chapter 8· Ⅱ

impolitic: if words or actions are impolitic, they are unwise and likely to cause offence or problems, especially in social situations

retaliate: to hurt someone or do something harmful because they have done or said something harmful to you

eg. Mr. Darcy, it is very ungenerous in you to mention all that you knew to my disadvantage in Hertfordshire — and, give me leave to say, very impolitic too — for it is provoking me to retaliate, and such things may come out as will shock your relations to hear.

amiss: wrong, not suitable, or not as expected

eg. Miss Bennet would not play at all amiss if she practised more, and could have the advantage of a London master.