To cease to have a skill or ability, to lose one's touch, to be washed up.
To become explosively angry; to lose one's temper.
To begin to laugh uncontrollably.
To feel devastated, or distraught, especially when one's sadness is overwhelming.
To lose one's mind, go crazy.
To lose control of a situation.
To cease to behave in a consistent and/or rational manner.
To lose sight of an important objective or principle; to act contrarily to one's own interests through concentrating on relatively unimportant matters.
Used other than figuratively or idiomatically: see lose, plot.