3
cutting edge
3
extreme(noun, limit, edge, boundary)
3
extremes(limit, edge, boundary)
3
front line
3
limiting factor(expression, idiom)
3
limits(border, borderline)
3
marchland(noun, territory, edge, borderline)
3
outpost(noun, border, station, borderline)
3
perimeter(noun, border, borderline, verge, threshold)
3
periphery(noun, border, borderline, verge, threshold)
3
skirt
3
stint(noun, limit)
3
termination(noun, limit, edge, border, borderline)
2
backcountry
2
boondocks
2
crease
2
demarcation
2
foreword
2
head
2
lap
11 years ago|10k views|share |citing 
APASmart Define. (2015). frontier thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/frontier/thesaurus/synonyms
ChicagoSmart Define. 2015. "frontier thesaurus" https://smartdefine.org/frontier/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, frontier thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/frontier/thesaurus/synonyms>.
MLASmart Define. "frontier thesaurus" 14 April 2015. Web. 22 September 2026. <https://smartdefine.org/frontier/thesaurus/synonyms>