Synonyms of frontier

frontier 1 of 2

noun

ˌfrən-ˈtir 

1

as in border

a region along the dividing line between two countries

the Apaches were once feared on both sides of the U.S.-Mexico frontier

Synonyms & Similar Words

• border
• borderland
• march
• no-man's-land

2

as in countryside

a rural region that forms the edge of the settled or developed part of a country

Alaska has been called America's last frontier

Synonyms & Similar Words

• countryside
• country
• backwater
• backwoods
• hinterland
• backcountry
• bush
• outback
• up-country
• (the) back of beyond
• outlands
• backland(s)
• boondocks
• boonies
• sticks

frontier

2 of 2

adjective

as in marginal

located at or near a border

a frontier town with a reputation for vice and lawlessness

Synonyms & Similar Words

• marginal
• outer
• outside
• borderline
• exterior
• external
• outermost
• outward
• outmost

Antonyms & Near Antonyms

• interior
• inner
• internal
• inside
• inward
• central
• middle
• innermost
• mid
• inmost

Example Sentences

Recent Examples of frontier

Noun

While space might be the final frontier, so much of the work done in space is designed to benefit us back here on Earth. — Chelsea Gohd, Space.com, 21 Oct. 2026

OpenAI and Google have come to an arrangement that will see the former’s frontier models arrive in Google Cloud services. — Ryan Whitwam, ArsTechnica, 21 Oct. 2026

Adjective

That worried Huang, who fears a Chinese rival, and White House officials, who believe Chinese dependence on non-frontier American chips is the best way to ensure a lead in AI. — Charlie Campbell, Time, 11 Dec. 2025