To become dull or dark (of color, shine, complexion); to lose brightness or luster.
古い写真は色がくすんで見える。
Old photos look faded/dull in color.
この銀のカップは空気に触れてくすんできた。
This silver cup has tarnished from exposure to the air.
長時間日光に当たると、布の色がくすむことがある。
If exposed to sunlight for a long time, fabric colors can become dull.
To be unassuming or inconspicuous; not stand out — used for people, styles, or impressions becoming plain or subdued.
彼女は派手な服を好まず、いつもくすんだ色の服を着ている。
She doesn't like flashy clothes and always wears clothes in subdued colors.
長年の苦労で彼の業績は世間にくすんでしまった。
After many years of hardship, his achievements have faded from public view.
新商品の宣伝不足でブランドの印象がくすんだ。
Insufficient promotion of the new product made the brand's image less striking.