Baccy is an informal British word for tobacco — the dried leaves people smoke, especially the loose kind they roll themselves. You hear it from older speakers, and in casual chat, more than in shops or classrooms. Someone might ask for “a bit of baccy” when they want to roll a cigarette, or keep it in a tin. It is friendly and a little old-fashioned; younger people in Britain still understand it, though actually many now just say tobacco, or talk about cigarettes as a finished thing. Baccy is the stuff itself. You would not put it in a school essay or a formal letter, and it is not a brand name.

菸草（英式口語，多指自己捲的菸絲）