Unforgettable means leaving an impression that stays with you for life. An unforgettable evening, truly unforgettable, an unforgettable face.
It is stronger than memorable, which only means worth recalling: something unforgettable stays whether you want it or not, which is why the word works for horrors as well as for holidays. Advertising uses it so freely that it has lost most of its force.
1adjectiveunforgettableLeaving so strong an impression that it stays with you for life.
“Swimming with dolphins was an unforgettable experience.”
unforgettable is a quality.
Un- plus forgettable, from Old English forgietan, to lose hold of in the mind.
Proto-Indo-European
*gʰed-
Proto-West Germanic
*fragetan — to give up, forget
Old English
forġietan — to forget
Middle English
forgeten
English
forget
English, today
unforgettable
From un- + forget + -able or un- + forgettable. forget comes from Middle English forgeten, forgiten, foryeten, forȝiten, from Old English forġietan (“to forget”) [influenced by Old Norse geta ("to get, to guess")], from Proto-West Germanic fragetan (“to give up, forget”). Equivalent to for- + get. Cognate with:
Etymology from Wiktionary, CC BY-SA