back up

verb

1. 1

   establish as valid or genuine

   Can you back up your claims?

2. 2

   become or cause to become obstructed

   The leaves clog our drains in the Fall

   The water pipe is backed up

3. 3

   make a copy of (a computer file) especially for storage in another place as a security copy

   You'd better back up these files!

4. 4

   move backwards from a certain position

   The bully had to back down

5. 5

   give moral or psychological support, aid, or courage to

   She supported him during the illness

   Her children always backed her up