undefined

adjective

un·​de·​fined ˌən-di-ˈfīnd 

: not defined: such as

a

: not clearly or precisely shown, described, or limited

undefined rules

undefined powers

a vague, undefined feeling of dread

… the true outlines of Clinton's foreign policy remain undefined.

—William Greider

b

: not provided with a definition

an undefined dictionary entry

Synonyms of undefined

• vague
• faint

Examples of undefined in a Sentence

plagued by undefined worries that kept her awake at night

Recent Examples on the Web

In a matter of minutes, my past and my still-undefined future crystallized. — Ayman M. Mohyeldin, Vanity Fair, 11 Sep. 2026

So a single article may include multiple policies, undefined acronyms or three different names for the same benefit across separate regions. — Chakkry Arunachalam, Forbes.com, 9 Sep. 2026

But the agreement subsequently collapsed as Washington and Tehran started fighting over shipping routes, which were left undefined in the deal. — Spencer Kimball,deena Zaidi, CNBC, 12 Aug. 2026

Still, despite the breakneck pace at which large language models and agentic AI are evolving, AI devices are still in the embryonic stage and very much undefined—a fact that may play to Ive’s strengths. — Emily Forlini, Fortune, 22 July 2026

Word History

First Known Use

1611, in the meaning defined above

Rhymes for undefined

• aligned
• alined
• assigned
• behind
• combined
• confined
• consigned
• crosswind
• declined
• defined
• designed
• divined