1. [ verb ] move backwards from a certain position
Synonyms: back_off back_down

"The bully had to back down"

Related terms: withdraw withdrawal
2. [ verb ] give moral or psychological support, aid, or courage to
Synonyms: support

"She supported him during the illness" "Her children always backed her up"

Related terms: help promote sponsor second patronize carry undergird support backing
3. [ verb ] establish as valid or genuine
Synonyms: back substantiate

"Can you substantiate your claims?"

Related terms: confirm reinforce vouch
4. [ verb ] (computer science) make a copy of (a computer file) esp. for storage in another place as a security cop

"You'd better back up these files!"

Related terms: copy computer
5. [ verb ] become or cause to become obstructed
Synonyms: clog choke_off congest choke foul clog_up

"The leaves clog our drains in the Fall" "The water pipe is backed up"

Related terms: unclog obstruct stuff silt_up gum_up crap_up congestion
Similar spelling:   backup