Definition: establish as valid or genuine
Usage: Can you back up your claims?
Main entry: clog, clog up, choke, choke off, congest, foul, back up
Definition: become or cause to become obstructed
Usage: The leaves clog our drains in the Fall; The water pipe is backed up
Main entry: back up
Definition: make a copy of (a computer file) especially for storage in another place as a security copy
Usage: You'd better back up these files!
Main entry: back down, back off, back up
Definition: move backwards from a certain position
Usage: The bully had to back down
Definition: give moral or psychological support, aid, or courage to
Usage: She supported him during the illness; Her children always backed her up