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

How a spouse chooses to inhabit a highly visible but largely undefined role is visually articulated through their fashion. — Anna Cafolla, Vogue, 25 Sep. 2026

An undefined position means scattershot and inconsistent AI usage at your company. — Rob Black, Forbes.com, 23 Sep. 2026

The role of the European Space Agency, perhaps NASA’s most enduring international partner, on the Moon Base program remains undefined. — Stephen Clark, ArsTechnica, 22 Sep. 2026

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