see the back of

see the back of

Be finished with, as in I hope we've seen the back of Betsy; she is terribly rude. This idiom transfers literally seeing someone's back because they are leaving to a more figurative and permanent departure. Also see see the last of.
See also: back, of, see

see the back of

be rid of an unwanted person or thing. British informal
See also: back, of, see