Vollgeraucht literally translates to "filled with smoke" or "smoked out". It's a vivid and somewhat informal compound adjective that paints a clear picture of a smoky environment.
In the song, the line "Zimmer vollgeraucht, seh' nicht weiter als ich muss" (Room filled with smoke, I don't see further than I have to) immediately sets a rebellious and hazy scene. It's not a word you hear every day, making it memorable and intriguing, and it perfectly captures the song's atmosphere of youthful abandon and blurred reality.
This song is about living fast and refusing to apologize for it. Since he was fifteen, the narrator has lived the rockstar life, and by now he doesn't care what anyone thinks.
The verses picture a wild night in with friends: a smoke-filled room, everyone chasing a good time, nobody wanting to go home. It's reckless, but the song treats it as freedom rather than regret. Life is short, so the narrator would rather live it now than hold back.
The English hook repeats the title, "Sorry, I'm not sorry." It's a shrug at anyone trying to tell him how to live, sung back and forth between badchieff and featured artist Tokio Hotel.