noun, used as a prefix, noun which may take the genitive case particle 'no', noun
semi-; half-; partially formed
Used as a prefix or noun modifier to indicate something is half-done, incomplete, or partially formed. Often appears in technical or descriptive compounds.
半成品はまだ完成していない。
The semi-finished product is not yet complete.
半成の状態で放置すると品質が落ちる。
If left in a half-finished state, the quality will deteriorate.
Compound of 半 (half) and 成 (become, form). The exact historical derivation is uncertain, but it follows a common Sino-Japanese word-formation pattern.