56 entries under extra topic. ×

16
alternate(noun, adjective, lower, copy, inferior)
12
reserve(noun, adjective, support, increase, lower)
8
alternative(noun, adjective, spare, substitute)
8
auxiliary(noun, adjective, support, increase, lower)
8
replacement(noun, adjective, reserve, agent)
8
spare(noun, adjective, support, reserve)
5
standby(noun, adjective, increase, reserve)
4
dummy(noun, replacement, alternative, alternate)
3
provisional(auxiliary, supernumerary)
2
ancillary(adjective, support, spare, inferior)
2
counterfeit(auxiliary, supernumerary)
2
ersatz(auxiliary, supernumerary)
2
imitation(auxiliary, supernumerary)
2
makeshift(substitute, replacement, alternative, alternate)
2
mock(auxiliary, supernumerary)
2
stopgap(substitute, replacement, alternative, alternate)
2
supplementary(adjective, support, increase, counterfeit, near)
2
temporary(reserve, substitute, replacement, alternative)
2
tentative(auxiliary, supernumerary)
2
vicarious(inferior, minor, subordinate, auxiliary)
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APASmart Define. (2015). backup thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/backup/thesaurus/synonyms
ChicagoSmart Define. 2015. "backup thesaurus" https://smartdefine.org/backup/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, backup thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/backup/thesaurus/synonyms>.
MLASmart Define. "backup thesaurus" 10 April 2015. Web. 20 September 2026. <https://smartdefine.org/backup/thesaurus/synonyms>