back up

1. 1.

   give moral or psychological support, aid, or courage to

   “She supported him during the illness”

   “Her children always backed her up”

   Synonymssupport

   Narrowersponsorpatronizehelppromoterootundergirdsecond
2. 2.

   move backwards from a certain position

   “The bully had to back down”

   Synonymsback offback down

   Broaderwithdraw
3. 3.

   establish as valid or genuine

   “Can you back up your claims?”

   Synonymsback

   Broaderconfirm
4. 4.

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

   “You'd better back up these files!”

   Broadercopy

   computer

5. 5.

   become or cause to become obstructed

   “The leaves clog our drains in the Fall”

   “The water pipe is backed up”

   Synonymsclogchoke offclog upcongestchokefoul

   Broaderobstruct

   Narrowergum upcrap upstuffsilt up

Questions about back up

What does back up mean?

back up means "give moral or psychological support, aid, or courage to". That is the primary sense; the word has 5 in total, listed in full on this page.

What is another word for back up?

Close synonyms include support, back off, back down, back, clog. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.

Is back up a common word?

back up is banded "Common" — everyday vocabulary in speech and writing. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.