7
questionable(adjective, clear, certain, uncertain, doubtful)
7
undecided(adjective, open, uncertain, definite, doubtful)
6
delimitation
6
dubious(adjective, clear, open, delicate, certain)
6
fringe(noun, edge, trim, border, frontier)
6
indefinite(adjective, open, uncertain, vague, unclear)
6
liminal
6
limit(noun, mark, top, stroke, extreme)
6
moot(adjective, ambiguous)
6
perimeter(noun, edge, border, frontier, trimming)
5
open(adjective, uncertain, nervous, unstable, doubtful)
5
brink(noun, edge, trim, border, frontier)
5
compass
5
suspicious(adjective, uncertain, nervous, doubtful, unsettled)
5
threshold(noun, edge, border, frontier, transitional)
5
unsettled(adjective, open, delicate, uncertain, unstable)
5
unstable(adjective, delicate, uncertain, nervous, doubtful)
4
clouded(adjective, clear, certain, uncertain, doubtful)
4
division
4
indeterminate(adjective, clear, certain, uncertain, anxious)
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APASmart Define. (2015). borderline thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/borderline/thesaurus/synonyms
ChicagoSmart Define. 2015. "borderline thesaurus" https://smartdefine.org/borderline/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, borderline thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/borderline/thesaurus/synonyms>.
MLASmart Define. "borderline thesaurus" 13 April 2015. Web. 20 September 2026. <https://smartdefine.org/borderline/thesaurus/synonyms>