noun
different thing; another thing; exception
Used to emphasize that something is fundamentally different from what was mentioned or expected, not just a variation. Often implies a qualitative gap.
彼の考え方は私とは別物だ。
His way of thinking is completely different from mine.
この料理は昨日のとは別物の美味しさだ。
This dish is on a whole different level of deliciousness compared to yesterday's.
Compound of 別 (different) and 物 (thing). The meaning is transparent from its components.