The antonyms for the word "pre-scribed" are "unprescribed," "non-prescribed," "non-standard," "atypical," and "unconventional." These terms indicate a lack of predetermined or pre-established rules or protocols. When a medication is unprescribed, for example, it means that its use is not authorized by a licensed physician or healthcare provider. Similarly, a non-prescribed treatment method may suggest that it is experimental or not yet recognized by established medical communities. Alternatively, an unconventional approach to a problem may signify a deviation from conventional methods. In short, antonyms for "pre-scribed" suggest the absence of set patterns, which can denote either flexibility or erraticism, depending on the context.