→ His employers backed him up.
→ My parents have always backed me up.
[+views, statement, theory, sb's words] confirmer
→ Her views are backed up by an official report on crime.
→ There is no evidence to back up your statement.
→ Radio signals received from the galaxy's centre back up the black hole theory.
If I say I was at your house, will you back me up? Si je dis que j'étais chez toi, tu peux le confirmer?
→ The girl denied being there, and the man backed her up.