dis‧ap‧pear S2 W2 [intransitive]
to become impossible to see any longer [= vanish; ≠ appear]
disappear behind/under/into etc
The sun had disappeared behind a cloud.
disappear from view/sight
David watched her car until it disappeared from view.
At this point the path seemed to disappear altogether (=disappear completely).
to be lost, or to become impossible to find [= vanish]:
The two girls disappeared while walking home from school.
My keys have disappeared again.
to stop existing:
The rain forest may disappear forever.