noun
degree of perfection; level of completion
Used to evaluate how finished, polished, or complete something is, often in creative, technical, or project contexts.
この作品は完成度が高い。
This work has a high degree of perfection.
プロジェクトの完成度はまだ50％だ。
The project's level of completion is still 50%.
品質 refers to general quality or grade, whereas 完成度 specifically focuses on how finished or polished something is.
Compound of 完成 (completion) and 度 (degree). The exact historical derivation is straightforward; the word is a modern Sino-Japanese formation.