noun
unfinished goods; unfinished product
Refers to a product that is not yet completed, typically in manufacturing or production contexts.
工場には未成品が山積みになっている。
The factory is piled high with unfinished goods.
Compound of 未 (mi, 'not yet') + 成品 (seihin, 'finished product'). The exact historical derivation is uncertain, but the meaning is transparent from its components.