If you say that something leaves an indelible impression, you mean that it is very unlikely to be forgotten.
例句
My visit to India in 1986 left an indelible impression on me...1986年的印度之行給我留下了難忘的印象。The war has made an indelible mark on the world.戰(zhàn)爭給世人留下了不可磨滅的印記。
ADJ
難以去除的;洗不掉的;擦不掉的
Indelible ink or an indelible stain cannot be removed or washed out.
例句
It leaves indelible stains on clothes.它會在衣物上留下洗不掉的污漬。...written in indelible ink.用不褪色墨水寫就
英英詞典釋義
Adverb
1. in an indelible manner;
"this tradition has left its mark indelibly upon the social, political, educational and industrial fabric of this country"