一去不复还
yī​qù​bù​fù​huán

gone forever

  1. 一 yī adverbnumeral
    [suddenness]
    Used before a verb to indicate that an action or situation occurs suddenly or unexpectedly.
  2. 去 qù verb
    to go
    to go to a place; to leave or depart; to go in order to do something
  3. 不复 不復 bù​fù
    to not return
    (literary) to not return; to not come back
  4. 还 還 huán verbnoun
    to go back
    to go or come back; to return to a place or restore to a former state