Some sources distinguish between "barbarisms" and "solecisms", using the former for errors in morphology and the latter for errors in syntax. So, using a nonstandard prefix would be a "barbarism". Insofar as "barbarism" is especially used for intrusions of one language into another, *unliterate* is a pretty good example (since Latinate roots usually prefer Latinate prefixes like *in-*, though there are plenty of exceptions like *unstable*).

Incidentally, *disclude* is a complicated example, because it used to be standard, and in fact, it's directly borrowed from a regularly-formed word attested in Classical Latin. The *Oxford English Dictionary* notes only that the relevant English sense is "Somewhat *rare* and *nonstandard* since 18th cent." So, be kind to the barbarists; someday your usages, too, will have passed.