amnesia
n. C / Un. a loss of memory, often caused by an injury or illness. You use this word when someone cannot remember things they used to know.
n. a partial or total loss of the ability to recall past experiences or information. Typically uncountable in clinical contexts; countable when referring to specific types or episodes.
He has amnesia from the car accident.
After the surgery, she suffered from temporary amnesia and could not recall the previous week.
The protagonist's selective amnesia serves as a narrative device, obscuring the truth until the final chapter reveals his repressed memories.
From modified Latin amnesia, from Ancient Greek ἀμνησία (amnēsía, “forgetfulness”), a noun derivation from μιμνήσκω (mimnḗskō, “to remind, to remember”) prefixed with the alpha privative.