- 1impossible to forget or remove synonym permanent The experience made an indelible impression on me. Her unhappy childhood left an indelible mark.
- 2(of ink, pens, etc.) leaving a mark that cannot be removed synonym permanent an indelible marker
NAmE//ɪnˈdɛləbli//
adverb That day is stamped indelibly on my memory.See indelible in the Oxford Advanced Learner's DictionaryCheck pronunciation: indelible