9
affix(noun, verb, continue, boost, attach)
9
increment(noun, increase, gain, rise, extra)
8
annex(noun, verb, part, advance, increase)
8
sequel(noun, increase, line, extra, addition)
8
supplementation
7
accompaniment(noun, part, rest, match, balance)
7
enrich(verb, improve, enhance, add, augment)
7
postscript(noun, increase, line, extra, addition)
7
subsidiary(noun, increase, extra, addition, extension)
6
augmentation(noun, increase, delay, rise, influence)
6
codicil(noun, act, part, increase, measure)
6
expand(verb, take, cover, advance, increase)
6
extra(noun, part, increase, addition, extension)
6
reinforce(verb, support, help, advance, increase)
5
accession(noun, increase, raise, rise, extra)
5
add-on(noun, increase, extra, addition, attachment)
5
add on(verb, expression, phrasal verb)
5
attachment(noun, act, increase, measure, extra)
5
auxiliary(noun, adjective, part, extra, addition)
5
boost(verb, support, take, cover, advance)
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APASmart Define. (2015). supplement thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/supplement/thesaurus/synonyms
ChicagoSmart Define. 2015. "supplement thesaurus" https://smartdefine.org/supplement/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, supplement thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/supplement/thesaurus/synonyms>.
MLASmart Define. "supplement thesaurus" 22 December 2015. Web. 21 September 2026. <https://smartdefine.org/supplement/thesaurus/synonyms>