back up

give moral or psychological support, aid, or courage to; "She supported him during the illness"; "Her children always backed her up"

move backwards from a certain position; "The bully had to back down"

establish as valid or genuine; "Can you back up your claims?"

make a copy of (a computer file) especially for storage in another place as a security copy; "You'd better back up these files!"

become or cause to become obstructed; "The leaves clog our drains in the Fall"; "The water pipe is backed up"