backup

How to sign: someone who takes the place of another (as when things get dangerous or difficult)
"the star had a stand-in for dangerous scenes"; "we need extra employees for summer fill-ins";

Similiar / Same: stand-in, reliever, backup man, fill-in, substitute, relief

Categories: compeer, equal, match, peer

Within this category: double, locum tenens, surrogate

back up

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

Similiar / Same: support

Within this category: help, patronize, promote, second, sponsor, undergird

backup

How to sign: (computer science) a copy of a file or directory on a separate storage device
"he made a backup in case the original was accidentally damaged or erased";

Similiar / Same: computer backup

Categories: duplicate, duplication