Undefined (adjective)

1. Not having been determined or fixed in meaning, form, or extent.
2. Not having been specified or clearly stated.

Origin:

From un- + defined, ultimately from latin definire, "to set limits or boundaries".

Examples:

1. The term was undefined, causing confusion in the discussion.
2. The variable was undefined, resulting in an error in the code.
3. The concept was undefined, leading to further research.
4. The boundaries were undefined, causing disputes among the neighbors.
5. The outcome was undefined, causing uncertainty about the future.