to cease or fail to remember; be unable to recall

to forget someone's name.

to omit or neglect unintentionally

I forgot to shut the window before leaving.

to leave behind unintentionally; neglect to take

to forget one's keys.

to omit mentioning; leave unnoticed.

to fail to think of; take no note of.

to neglect willfully; disregard or slight.

to cease or omit to think of something. ?

forget oneself, to say or do something improper or unbefitting one's rank, position

or character.