simplesitesplus.net -Undefined undefined (ˌʌndɪˈfaɪnd) adj not defined or made clear: the job has remained undefined. ˌundeˈfinable adj un•de•fined (ˌʌn dɪˈfaɪnd) adj. 1. not defined or explained. 2. indefinite in form or extent: an undefined feeling of sadness. [1605–15] un`de•fin′ed•ly, adv. un`de•fin′ed•ness, n. ThesaurusAntonymsRelated
Define Undefined at dictionary.com. adjective. without fixed limits; indefinite in form, extent, or application: undefined authority; undefined feelings of sadness. not given meaning or significance, as by a definition; not defined or explained: an undefined term.
Undefined synonyms, undefined antonyms. With an undefined feeling of awe, she looked in the countenance of her friend. The position of the reputed slave in England was undefined and doubtful.
Undefined. While it is possible to use it as an identifier (variable name) in any scope other than the global scope (because undefined is not a reserved word), doing so is a very bad idea that will make your code difficult to maintain and debug.