transcription, транскрипция: [ ɪndelɪb(ə)l ]
If you say that something leaves an indelible impression, you mean that it is very unlikely to be forgotten.
My visit to India in 1986 left an indelible impression on me...
ADJ : usu ADJ n
• in‧del‧ibly
The horrors he experienced are imprinted, perhaps indelibly, in his brain.
ADV : ADV with v