Impolite means not being polite, not having good manners, or not showing proper respect.
Ex: Most people consider it terribly impolite to talk in the cinema, because it makes it much harder for other people to hear what is going on in the film.
Ex: Your behaviour to the salesman was unbelievably impolite. You should never ask a stranger how much money he makes; it is not good manners.
The opposite of impolite is polite. “When you are polite to” someone, you show respect and good manners to that person.
Ex: The mother instructed her children to be very polite to people who visit them. They were to look people in the eye, speak loud enough to be heard, and smile.
Ex: It is polite behavior to thank the host of the party for inviting you before you leave, so we need to find Mrs. Macmurphy and say "thank you" to her.
Disrespectful means not showing proper respect, not showing courtesy, not being polite. A disrespectful person does not treat others properly.
Ex: The defendant in the murder trial showed a disrespectful attitude towards the judge, telling him he didn't care what he said, and that if the judge sent him to jail, he would escape.
Ex: Martha's three grown children are very disrespectful toward her. They think nothing of telling her what to do instead of asking her politely.
When you treat someone with no respect, you disrespect them. It can be also used as a noun. The phrase no disrespect is often used when you are criticizing someone but want them to know that you still admire and respect them.
Ex: No disrespect to your cooking skills, Sophia, but this casserole is just not one of your best culinary efforts. Where did you get the recipe for this?
Ex: Mrs. Worthington, I've got to tell you that I've studied many history courses, but yours has been the most difficult to comprehend, no disrespect.