Real Dictionary

forget
verb: If you forget something or forget how to do something, you cannot think of it or think how to do it, although you knew it or knew how to do it in the past.
verb: If you forget something or forget to do it, you fail to think about it or fail to remember to do it, for example because you are thinking about other things.
verb: If you forget something or someone, you deliberately put them out of your mind and do not think about them any more.
verb: If you forget something that you had intended to bring with you, you do not bring it because you did not think about it at the right time.
verb: If you forget yourself, you behave in an uncontrolled or unacceptable way, which is not the way in which you usually behave.

forget in American English
to lose (facts, knowledge, etc.) from the mind; fail to recall; be unable to remember
intransitive verb: to cease or omit to think of something
transitive verb: to cease or fail to remember; be unable to recall

forget in British English
verb: to fail to recall (someone or something once known); be unable to remember