Wiktionary
uncastable
a. 1 That cannot be cast (filled with, or allocated, a theatrical role). 2 (context computing programming English) That cannot be cast (converted to other data types). 3 (context medicine English) That cannot be set in a cast. 4 That cannot be used for, or produced through, casting (manufacturing with a mould).
Usage examples of "uncastable".
Now that the Nisibisi power globes' destruction had made simple spells uncastable and love potions useless, now that sympathetic magic was no longer so, the Mageguild adepts feared not merely for their income.