禁物
きんもつ · kinmotsu · JLPT N1 · noun
forbidden thing
禁 = forbid + 物 = thing, so 禁物 = a forbidden thing (taboo)
禁 means ban or prohibit, and 物 means thing or object. Together they name anything off-limits, such as a taboo subject or a no-go behaviour. The word is often used in phrases like 禁物です, meaning it is forbidden.