noun
inferior copy; degraded copy
Refers to a copy that has lost quality compared to the original, often used for digital or physical reproductions.
この画像は劣化コピーで、元の写真よりずっと不鮮明だ。
This image is a degraded copy, much blurrier than the original photo.
何度も複写すると劣化コピーになってしまう。
If you photocopy it many times, it becomes an inferior copy.