forgotten
v.v. unable to remember something or someone. You use this when a piece of information has left your mind.
v. the past participle of forget, indicating a failure to recall information or a neglect of a duty or person.
I have forgotten my keys again.
The password was written in an old notebook that had been forgotten in the attic for years.
While the details of the contract have been forgotten by most of the staff, the legal department maintains a digital archive for compliance purposes.
Morphologically forgot + -en.
As a past participle, it is used in perfect tenses with 'have' or as an adjective before a noun.
I have forgot my keysI have forgotten my keysIn standard British and American English, 'forgotten' is the required past participle form for perfect tenses, while 'forgot' is the simple past.