Synonyms of standby

1 Syllable

temp, sub

2 Syllables

stalwart, fill-in, mainstay, locum, double, stand-in, backup, relief, waitlist

3 Syllables

deputy, sustainer, assistant, changeling, maintainers, pinch-hitter, upholder, supplanter, reserve, upholders, maintainer, successor

4 Syllables

succedaneum, temporary, understudy, replacement