noun
unfinished product; work in progress
Refers to a product or article that is not yet completed; used in manufacturing, crafts, or creative contexts.
この未製品は、あと少し手を加えれば完成します。
This unfinished product will be complete with just a little more work.
完成品 is the finished product, the opposite of 未製品.
Compound of 未 (mi, 'not yet') + 製品 (seihin, 'manufactured product'). The reading is straightforward on'yomi.