In English ass is used as a swear word, it is also used in slang to make things more intense. Examples: “This is ass.” This is bad. “You are an ass.” You are rude/bad. “This is badass.” This is cool. “You are badass.” You are cool. “You smartass.” You sarcastic asshole. “You dumbass.” An insult, you are dumb. “Hey asshat!” Hey you, but rude. “This is a long-ass ride.” The ride is taking a long time.
All of these are mildly impolite or casual language.