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

Artificial intelligence is big, scary, exciting and more than just a little undefined. — Evan Clark, Footwear News, 28 Oct. 2026

Still, several categories in New York's law are broadly worded or undefined, Gluck said. — ABC News, 28 Oct. 2026

The show’s title is inspired by the fable that the Nile springs from the Moon Mountains, an undefined range south of the country. — Sam Cochran, Architectural Digest, 27 Oct. 2026

Crowds in an anachronistic fashion mashup of 1950s fedoras, 1940s newsboy caps, and 1960s pillbox hats celebrate some undefined New Year’s Eve of yore. — Justin Davidson, Curbed, 1 Oct. 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