noun
unwanted items; refuse; waste material
Refers to things that are no longer needed or useful, often in contexts of disposal, decluttering, or waste management.
引っ越しの前に不要物を処分した。
I disposed of unwanted items before moving.
この箱には不要物を入れてください。
Please put waste material in this box.
廃棄物 is a technical/legal term for 'waste' or 'discarded materials', whereas 不要物 is broader and can include personal belongings that are simply no longer needed.
Compound of 不要 (fuyō, 'unnecessary') + 物 (butsu, 'thing'). The reading ふようぶつ follows standard on'yomi.