unratable
/ˌʌnˈreɪtəbəl/ or /ənˈreɪtəbəl/Definitions
1. adjective
Not capable of being rated or valued.
“The unratable nature of the artwork made it difficult to price.”
2. adjective
Impossible to rate or evaluate.
“The unratable quality of the movie made it hard to give a review.”