UNDEFENDED Synonyms: 49 Similar and Opposite Words

undefended

adjective

ˌən-di-ˈfen-dəd

Definition of undefended

as in vulnerable

lacking protection from danger or resistance against attack the cowardly soldiers fled, leaving the palace undefended

Synonyms & Similar Words

Relevance

Antonyms & Near Antonyms

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of undefended The lack of range of Coastal Command aircraft left an undefended area known as the Mid-Atlantic Gap, rendering merchant shipping and their escorts without air cover and vulnerable to attack. — Mark Wood, TheWeek, 7 Jan. 2026 Trouba opened the scoring in the first period with an undefended slap shot after an egregious Blackhawks turnover. — CBS News, 7 Dec. 2025 Mark Collins, who was born and raised in Newfoundland, Canada, said Canadians have long treasured their friendship with the United States and the fact that the US-Canada border is the longest undefended border on the planet. — Matt Egan, CNN Money, 13 Oct. 2025 Like the global undersea cable network, the United States’ deep-water drilling infrastructure is rapidly expanding while remaining almost entirely undefended. — Robert Martinage, Foreign Affairs, 1 Jan. 2015 See All Example Sentences for undefended

Recent Examples of Synonyms for undefended

Adjective

The fourth, the Indian rhinoceros, is vulnerable, its habitat shrinking rapidly as fragmented and isolated population groups spread across a shattered landscape littered with invasive plant species poisonous to the animals.

— Literary Hub, Literary Hub, 22 Sep. 2026
The storms destroyed sections of a seawall and historic boardwalk in Long Beach, shuttered a long-vulnerable stretch of coastal railway in San Clemente, and further threatened Carlsbad Boulevard, also known as Old Highway 101, in Carlsbad.

— Grace Toohey, Los Angeles Times, 21 Sep. 2026

Definition of vulnerable

Adjective

Analysts say until there are clear guidelines on who can regulate prediction markets — possibly from the Supreme Court — DraftKings could be susceptible to headline volatility in the short term.

— Ananya Chetia, CNBC, 22 Sep. 2026
Yet in the twentieth century, when countries around the world prioritized the suppression of all wildfires, many areas became overgrown and susceptible to firestorms.

— Ingfei Chen, New Yorker, 18 Sep. 2026

Definition of susceptible

Adjective

Women of color are some of the most unprotected people in society.

— Matt Donnelly, Variety, 16 Sep. 2026
The deal — agreed upon in late June — would send Brandon Ingram, Gradey Dick, two unprotected first-rounders, a first-round pick swap and two second-rounders to the Clippers.

— Matt Schubert, New York Times, 14 Sep. 2026

Definition of unprotected

Browse Nearby Words

undefeated

undefended

undefiled

See all Nearby Words

Cite this Entry

Style

“Undefended.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/undefended. Accessed 27 Sep. 2026.

Copy Citation

Synonyms of undefended

adjective

Example Sentences

Browse Nearby Words

Cite this Entry

More from Merriam-Webster

Word of the Day

bellwether

Popular in Grammar & Usage

Do You Need a New Language Peeve?

More Commonly Mispronounced Words

Why do we use apostrophes to show possession?

Merriam-Webster’s Great Big List of Words You Love to Hate

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Popular in Wordplay

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Back to School Vocabulary

14 Phobias You Probably Haven't Heard Of

The Words of the Week - Sept. 25

Popular

Do You Need a New Language Peeve?

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Games & Quizzes