Anything that's haram is forbidden or sinful for an observant Muslim. Islamic law considers both disrespecting one's parents and eating pork to be haram.
Activities or actions that harm one's self or other people are generally considered to be haram. Many of these are specifically prohibited in the Quran, including consuming certain food and drink, stealing or cheating to obtain money, and crimes of violence. It's also haram to break a fast in the daytime during Ramadan or eat meat that's not slaughtered according to Islamic law. In Arabic, haram means "forbidden."