Indeterminate means impossible to determine, establish precisely, or decide with certainty. When something is indeterminate, you can't pin down its exact value, meaning, or outcome.

In mathematics, indeterminate describes expressions that can't be given a single, well-defined value in the usual way. For example, the expression 0 ÷ 0 is called indeterminate because it does not have one unique answer. When an architect measures a beam that's somewhere between 8 and 9 feet but can't measure more precisely with available tools, that measurement remains indeterminate until better tools are available.

The word also describes situations where the answer or outcome stays uncertain. When a tied soccer game goes to penalty kicks, the winner is indeterminate until those final shots. If you're reading a mystery story and can't figure out who committed the crime because the clues point equally toward several suspects, the guilty party remains indeterminate (at least until you finish the book).

The opposite would be determinate, meaning definite, fixed, or precisely established.