Generally treated as an uncountable noun, though a rare plural ‘forgetfulnesses’ is attested.
Translations
Her forgetfulness often leads to missed appointments.
Её забывчивость часто приводит к пропущенным встречам.
The old traditions have fallen into forgetfulness.
Старые традиции погрузились в забвение.
Definitions
The quality or state of being unable to remember things. Her forgetfulness often led to misplaced keys and missed appointments.
A tendency to forget things easily. His forgetfulness was becoming a concern for his family.
An instance or act of failing to remember something. A brief forgetfulness of the code caused a delay at the door.